§ 2. The Argument in the Concrete

But it is our task to criticize the theory of transformism, and not to throw a life-line to fixism, by advocating gradual formation of species as the only feasible alternative to gradual transformation of species. Perhaps, this particular life-line will not be appreciated any way; for the fixist may, not without reason, prefer to rest his case on the contention that the intrinsic time-value of geological formations is far too problematic for certain conclusions of any sort. In maintaining this position, he will have the support of some present-day geologists, and can point, as we shall see, to facts that seem to bear out his contention. In fact, the cogency of the palæontological argument appears to be at its maximum in the abstract, and to evaporate the moment we carry it into the concrete. The lute seems perfect, until we begin to play thereon, and then we discover certain rifts that mar the effect. It is to these rifts that our attention must now be turned.

The first and most obvious flaw, in the evolutionary interpretation of fossil series, is the confounding of succession with filiation. Thinkers, from time immemorial, have commented on the deep chasm of distinction, which divides historical from causal sequence, and philosophers have never ceased to inveigh against the sophistical snare of: Post hoc, ergo propter hoc. That one form of life has been subsequent in time to another form of life is, in itself, no proof of descent. “Let us suppose,” says Bather, “all written records to be swept away, and an attempt made to reconstruct English history from coins. We could set out our monarchs in true order, and we might suspect that the throne was hereditary; but if on that assumption we were to make James I, the son of Elizabeth—well, but that’s just what palæontologists are constantly doing. The famous diagram of the Evolution of the Horse which Huxley used in his American lectures has had to be corrected in the light of the fuller evidence recently tabulated in a handsome volume by Prof. H. F. Osborn and his coadjutors. Palæotherium, which Huxley regarded as a direct ancestor of the horse, is now held to be only a collateral, as the last of the Tudors were collateral ancestors of the Stuarts. The later Ancitherium must be eliminated from the true line as a side branch—a Young Pretender. Sometimes an apparent succession is due to immigration of a distant relative from some other region—‘The glorious House of Hanover and Protestant Succession.’ It was, you will remember, by such migrations that Cuvier explained the renewal of life when a previous fauna had become extinct. He admitted succession but not descent.” (Science, Sept. 17, 1920, p. 261.)

But, if succession does not imply descent, descent, at least, implies succession, and the fact that succession is the necessary corollary of descent, may be used as a corrective for the erroneous allocations made by neontologists on the basis of purely morphological considerations. The priority of a type is the sine qua non condition of its being accepted as ancestral. It is always embarrassing when, as sometimes happens, a “descendant” turns out to be older than, or even coëval with, his “ancestor.” If, however, the historical position of a form can be made to coincide with its anatomical pretensions to ancestry, then the inference of descent attains to a degree of logical respectability that is impossible in the case of purely zoölogical evidence. Recent years have witnessed a more drastic application of the historical test to morphological speculations, and the result has been a wholesale revision of former notions concerning phylogeny. “I could easily,” says Bather, “occupy the rest of this hour by discussing the profound changes wrought by this conception on our classification. It is not that orders and classes hitherto unknown have been discovered, not that some erroneous allocations have been corrected, but the whole basis of our system is being shifted. So long as we were dealing with a horizontal section across the tree of life—that is to say, with an assemblage of approximately contemporaneous forms—or even with a number of such horizontal sections, so long were we confined to simple description. Any attempt to frame a causal connection was bound to be speculative.” (Ibidem, p. 258.) Whether zoölogists will take kindly to this “shifting of the whole basis” of classification, remains to be seen. Personally, we think they would be very ill-advised to exchange the solid observational basis of homology for the scanty facts and fanciful interpretations of palæontologists.

The second stumbling block in the path of Transformism is the occurrence of convergence. We have seen that, in the palæontological argument, descent is inferred conjointly from similarity and succession, and that, in the abstract, this argument is very persuasive. One of the concrete phenomena, however, that tend to make it inconsequential, is the undoubted occurrence of convergence. Prof. H. Woods of Cambridge, in the Introduction to the 5th edition of his “Palæontology” (1919), speaks of three kinds of convergence (cf., pp. 14, 15, 16), which, as a matter of convenience, we may term the parallelistic, the radical, and the adaptational, types of convergence. A brief description of each type will serve to elucidate its nature and its significance:

(1) Parallelistic convergence implies the appearance of parallel modifications in the homologous parts of organisms regarded as diverging from common stock in two distinct collateral lines, that were independent at the time of the appearance in both of the said parallel modifications. Speaking of the fossil cœlenterates known as Graptolites, Professor Woods says: “In some genera the hydrothecæ of different species show great variety of form, those of one species being often much more like those of a species belonging to another genus than to other species of the same genus.” (“Palæontology,” 5th ed., 1919, p. 69.) As another instance of this phenomenon, the case of the fossil ungulates of South America, spoken of as Litopterna, may be cited, and the case is peculiarly interesting because of its bearing on that pièce de résistance of palæontological evidence, the Pedigree of the Horse. “The second family of Litopterna,” says Wm. B. Scott, “the Proterotheriidæ, were remarkable for their many deceptive resemblances to horses. Even though those who contend that the Litopterna should be included in the Perissodactyla should prove to be in the right, there can be no doubt that the proterotheres were not closely related to the horses, but formed a most striking illustration of the independent acquisition of similar characters through parallel or convergent development. The family was not represented in the Pleistocene, having died out before that epoch, and the latest known members of it lived in the upper Pliocene.... Not that this remarkable character was due to grotesque proportions; on the contrary, they looked far more like the ordinary ungulates of the northern hemisphere than did any of their South American contemporaries; it is precisely this resemblance that is so notable.... The feet were three-toed, except in one genus (Thoatherium) in which they were single-toed, and nearly or quite the whole weight was carried upon the median digit, the laterals being mere dew-claws. The shape of the hoofs and the whole appearance of the foot was surprisingly like those of the three-toed horses, but there were certain structural differences of such great importance, in my judgment, as to forbid the reference of these animals, not merely to the horses, but even to the perissodactyls.” (“A History of Land Mammals in the Western Hemisphere,” p. 499.)

For this sort of parallelism, the Lamarckian and Darwinian types of evolution by addition can offer no rational explanation. It could, perhaps, be accounted for upon the Batesonian hypothesis of evolution by loss of inhibition, that is to say, the coincident appearance of convergent characters in collateral lines might be interpreted as being due to a parallel loss in both lines of the inhibitive genes, which had suppressed the convergent feature in the primitive or common stock. We say that the convergence might be so interpreted, because the interpretation in question would, at best, be merely optional and not at all necessary; for in the third, or adaptational, type of convergence, we shall see instances of parallel modifications occurring in completely independent races, whose morphology and history alike exclude all possibility of hereditary connection between them. Hence, even in the present case, nothing constrains us to accept the genetic interpretation.

(2) Radical convergence, which Woods styles heterogenetic homœomorphy, is described by him as follows: “Sometimes two groups of individuals resemble each other so closely that they might be regarded as belonging to the same genus or even to the same species (italics mine), but they have descended from different ancestors since they are found to differ in development (ontogeny) or in their palæontological history; this phenomenon, of forms belonging to different stocks approaching one another in character, is known as convergence or heterogenetic homœomorphy, and may occur at the same geological period or at widely separated intervals. Thus the form of oyster known as Gryphaea has originated independently from oysters of the ordinary type in the Lias, in the Oölites, and again in the Chalk; these forms found at different horizons closely resemble one another and have usually been regarded as belonging to one genus (Gryphaea), but they have no direct genetic connection with one another.” (“Palæontology,” 5th ed., 1919, p. 15.) Comment is almost superfluous. If even specific resemblance is no proof of common origin, then what right have we to interpret any resemblance whatever in this sense? With such an admission, the whole bottom drops out of the evolutionary argument. When the theory of descent is forced to account for heterogenetic resemblance at expense of all likelihood and consistency, when it cannot save itself except by blowing hot and cold with one breath, one is tempted to exclaim: “Oh, why bother with it!”

(3) Adaptational convergence is the occurrence of parallel modifications due to analogous specialization in unrelated forms, whose phylogeny has been obviously diverse. “Also, animals belonging to quite distinct groups,” says Woods, “may, when living under similar conditions, come to resemble one another owing to the development of adaptive modifications, though they do not really approach one another in essential characters; thus analogous or parallel modifications may occur in independent groups—such are the resemblances between flying reptiles (Ornithosaurs) and birds, and between sharks, icthyosaurs and dolphins.” (Op. cit., p. 16.) As this type of convergence has been discussed in a previous article, with reference to the mole and mole-cricket, it need not detain us further.

All these types of convergence, but especially the second type, are factual evidence of the compatibility of resemblance with independent origin, and the fact of their occurrence tends to undermine the certainty of the phylogenetic inferences based on fossil evidence; all the more so, that, thanks to its bad state of preservation, and the impossibility of dissection, even superficial resemblances may give rise to false interpretations. And, as for the cases of radical convergence, there is no denying that they strike at the very heart of the theory of descent.

The third difficulty for Transformism arises from the discontinuity of the geological record. It was one of the very first discrepancies to be discovered between evolutionary expectation and the actual results of research. The earliest explorations revealed a state of affairs, that subsequent investigations have failed to remedy: on the one hand, namely, a notable absence of intermediate species to bridge the gaps between the fossil genera, and on the other hand, the sudden and simultaneous appearance of numerous new and allied types unheralded by transitional forms. Since Darwin had stressed the gradualness of transmutation, the investigators expected to find the transitional means more numerous than the terminal extremes, and were surprised to find, in the real record of the past, the exact reverse of their anticipation. They found that the classes and families of animals and plants had always been as widely separated and as sharply differentiated as they are today, and that they had always formed distinct systems, unconnected by transitional links. The hypothetical “generalized types,” supposed to combine the features of two or three families, have never been found, and most probably never will be; for it is all but certain that they never existed. Occasionally, it is true, palæontologists have discovered isolated types, which they interpreted as annectant forms, but a single pier does not make a bridge, and only too often it chanced that the so-called annectant type, though satisfactory from the morphological standpoint, was more recent than the two groups, to which it was supposed to be ancestral. But it will make matters plainer, if we illustrate what is meant by the discontinuity or incompleteness of the fossil record, by reference to some concrete series, such as the so-called Pedigree of the Horse.

Whenever a series of fossils, arranged in the order of their historical sequence, exhibits a gradation of increasing resemblance to the latest form, with which the series terminates, such a series is called a palæontological pedigree, and is said to represent so many stages in the racial development or phylogeny of the respective modern type. The classical example of this sort of “pedigree” is that of the Horse. It is, perhaps, one of the most complete among fossil “genealogies,” and yet, as has been frequently pointed out, it is, as it stands, extremely incomplete. Modern representatives of the Equidae, namely, the horse, the ass and the zebra, belong to a common genus, and are separated from one another by differences which are merely specific, but the differences which separate the various forms, that compose the “pedigree of the Horse,” are generic. We have, to borrow Gerard’s simile, nothing more than the piers of the evolutionary bridge, without the arches, and we do not know whether there ever were any arches. There is, indeed, a sort of progression, e.g., from the four-toed to a one-toed type, so that the morphological gradation does, in some degree, coincide with temporal succession. But, on the other hand, the fossil forms, interpreted as stages in the phylogeny of the Horse, are separated from one another by gaps so enormous, that, in the absence of intermediate species to bridge the intervals, it is practically impossible, particularly in the light of our experimental knowledge of Genetics, to conceive of any transition between them. Nor is this all. The difficulty is increased tenfold, when we attempt to relate the Equidae to other mammalian groups. Fossil ungulates appear suddenly and contemporaneously in the Tertiary of North America, South America and Europe, without any transitional precursors, to connect them with the hypothetical proto-mammalian stock, and to substantiate their collaterality with other mammalian stocks.

To all such difficulties the evolutionist replies by alleging the incompleteness of the geological record, and modern handbooks on palæontology devote many pages to the task of explaining why incompleteness of the fossil record is just what we should expect, especially in the case of terrestrial animals. The reasons which they assign are convincing, but this particular mode of solving the difficulty is a rather precarious one. Evolutionists should not forget that, in sacrificing the substantial completeness of the record to account for the absence of intermediate species, they are simultaneously destroying its value as a proof of the relative position of organic types in time. Yet this, as we have seen, is precisely the feature of greatest strategic value in the palæontological “evidence” for evolution. We must have absolute certainty that the reputed “ancestor” was in existence prior to the appearance of the alleged “descendant,” or the peculiar force of the palæontological argument is lost. It would be preposterous for the progeny to be prior to, or even coëval with, the progenitor, and so we must be quite sure that what we call “posterity” is really posterior in time. Now the sole argument that palæontology can adduce for the posteriority of one organic type as compared with another is the negative evidence of its non-occurrence, or rather of its non-discovery, in an earlier geological formation. The lower strata do not, so far as is known, contain the type in question, and so it is concluded that this particular form had no earlier history. Such an inference, as is clear, is not only liable to be upset by later discoveries, but has the additional disadvantage of implicitly assuming the substantial completeness of the fossil record, whereas the absence of intermediate species is only explicable by means of the assumed incompleteness of the selfsame record. The evolutionist is thus placed in the dilemma of choosing between a substantially complete, and a substantially incomplete, record. Which of the alternatives, he elects, matters very little; but he must abide by the consequences of his decision, he cannot eat his cake and have it.

When the evolutionist appeals to the facts of palæontology, it goes without saying that he does so in the hope of showing that the differences, which divide modern species of plants and animals, diminish as we go backward in time, until the stage of identity is reached in the unity of a common ancestral type. Hence from the very nature of the argument, which he is engaged in constructing, he is compelled to resort to intermediate types as evidence of the continuity of allied species with the hypothetical ancestor, or common type, whence they are said to have diverged. Now, even supposing that his efforts in this direction were attended with a complete measure of success, evidence of this kind would not of itself, as we shall see, suffice to demonstrate the common origin of the extremes, between which a perfect series of intergradent types can be shown to mediate. Unquestionably, however, unless such a series of intergradent fossil species can be adduced as evidence of the assumed transition, the presumption is totally against the hypothesis of transformism.

Now, as a matter of fact, the geological record rarely offers any evidence of the existence in the past of intermediate species. For those, who have implicit confidence in the time-value of geological “formations,” there are indications of a general advance from lower to higher forms, but, even so, there is little to show that this seeming progress is to be interpreted as an increasing divergence from common ancestral types. With but few exceptions, the fossil record fails to show any trace of transitional links. Yet pedigrees made up of diverse genera are poor evidence for filiation or genetic continuity, so long as no intermediate species can be found to bridge the chasm of generic difference. By intermediate species, we do not mean the fabulous “generalized type.” Annectants of this kind are mere abstractions, which have never existed, and never could have existed. We refer rather to actual fossil types separated from one another by differences not greater than specific; for “not until we have linked species into lineages,” can fossil pedigrees lay claim to serious attention.

But let us suppose the case for evolution to be ideally favorable, and assume that in every instance we possessed a perfect gradation of forms between two extremes, such, for example, as occurs in the Ammonite series, even then we would be far from having a true demonstration of the point at issue. Bateson has called our attention to the danger of confounding sterile and instable hybrids with intergradent species. “Examine,” he says, “any two thoroughly distinct species which meet each other in their distribution, as for instance, Lychnis diurna and vespertina do. In areas of overlap are many intermediate forms. These used to be taken to be transitional steps, and the specific distinctness of vespertina and diurna was on that account questioned. Once it is known that these supposed intergrades are merely mongrels between the two species the transition from one to the other is practically beyond our powers of imagination to conceive. If both these can survive, why has their common parent perished? Why, when they cross, do they not reconstruct it instead of producing partially sterile hybrids? I take this example to show how entirely the facts were formerly misrepresented.” (Heredity, Smithson. Inst. Rpt. for 1915, p. 369.)

Similarly, T. H. Morgan has shown, with reference to mutants, the fallacy of inferring common descent from the phenomenon of intergradence, and what holds true for a series of intergradent mutants would presumably also hold true of a series of intergradent species, could such a series be found and critically distinguished from hybrid and mutational intermediates. In short, the Darwinian deduction of common origin from the existence of intergradence must now be regarded as a thoroughly discredited argument. “Because we can often arrange the series of structures in a line extending from the very simple to the more complex, we are apt to become unduly impressed by this fact and conclude that if we found the complete series we should find all the intermediate steps and that they have arisen in the order of their complexity. This conclusion is not necessarily correct.” (“A Critique of the Theory of Evolution,” p. 9.) Having cited such a series of gradational mutations ranging between the long-winged, and completely wingless condition, in the case of the Vinegar Fly (Drosophila melanogaster), as well as two similar graded series based on pigmentation and eye color, he concludes: “These types, with the fluctuations that occur within each type, furnish a complete series of gradations; yet historically they have arisen independently of each other. Many changes in eye color have appeared. As many as thirty or more races differing in eye color are now maintained in our cultures. Some of them are so similar that they can scarcely be separated from each other. It is easily possible beginning with the darkest eye color, sepia, which is a deep brown, to pick out a perfectly graded series ending with pure white eyes. But such a serial arrangement would give a totally false idea of the way the different types have arisen; and any conclusion based on the existence of such a series might very well be entirely erroneous, for the fact that such a series exists bears no relation to the order in which its members have appeared.” (Op. cit., pp. 12, 13.) Such facts must give us pause in attaching undue importance to phenomena like the occurrence of a gradual complication of sutures in the Chalk Ammonites, particularly as parallel series of perfectly similar sutures occurs “by convergence” in the fossil Ceratites, which have no genetic connection with the Ammonites. (Cf. Woods’ “Palæontology,” 5th ed., p. 16.)

But, if even mutational and specific intergradents are not sufficient evidence of common ancestry, what shall we say of a discontinuous series, whose links are separate genera, orders, or even classes, instead of species. Even the most enthusiastic transformist is forced to admit the justice of our insistence that the gaps which separate the members of a series must be reduced from differences of the generic, to differences of the specific, order, before that series can command any respect as hypothetical “genealogy.” “You will have observed,” says F. A. Bather, “that the precise methods of the modern palæontologist, on which this proof is based, are very different from the slap-dash conclusions of forty years ago. The discovery of Archæopteryx, for instance, was thought to prove the evolution of birds from reptiles. No doubt it rendered that conclusion extremely probable, especially if the major promise—that evolution was the method—were assumed. But the fact of evolution is precisely what men were then trying to prove. These jumpings from class to class or from era to era, by aid of a few isolated stepping-stones, were what Bacon calls anticipations “hasty and premature but very effective, because as they are collected from a few instances, and mostly from those which are of familiar occurrence, they immediately dazzle the intellect and fill the imagination.” (Nov. Org., I, 28.) No secure step was taken until the modern palæontologist began to affiliate mutation with mutation and species with species, working his way back, literally inch by inch, through a single small group of strata. Only thus could he base on the laboriously collected facts a single true interpretation; and to those who preferred the broad path of generality his interpretations seemed, as Bacon says they always “must seem, harsh and discordant—almost like mysteries of faith.” ... Thus by degrees we reject the old slippery stepping-stones that so often toppled us into the stream, and, foot by foot, we build a secure bridge over the waters of ignorance.” (Science, Sept. 17, 1920, pp. 263, 264.)

We cannot share Bather’s confidence in the security of a bridge composed of even linked species. Let such a series be never so perfect, let the gradation be never so minute, as it might conceivably be made, when not merely distinct species, but also hybrids, mutants and fluctuants are available as stopgaps, the bare fact of such intergradation tells nothing whatever concerning the problem of genetical origin and specific relationship. The species-by-species method does, however, represent the very minimum of requirement imposed upon the palæontologist, who professes to construct a fossil pedigree. But, when all is said and done, such a method, even at its best, falls considerably short of the mark. However perfectly intergradent a series of fossils may be, the fact remains that these petrified remnants of former life cannot be subjected to breeding tests, and that, in the consequent absence of genetical experimentation, we have no means of determining the real bearing of these facts upon the problem of interspecific relationship. Only the somatic characters of extinct floras and faunas have been conserved in the rock record of the past, and even these are often rendered dubious, as we shall see presently, by their imperfect state of preservation. Now, it is solely in conjunction with breeding experiments, that somatic characters can give us any insight into the nature of the germinal constitution of an organism, which, after all, is the cardinal consideration upon which the whole question of interspecific relationship hinges. All inferences, therefore, regarding the descent of fossil forms are irremediably speculative and conjectural. When we are dealing with living forms, we can always check up the inferences based on somatic characteristics by means of genetical experiments, and in so doing we have found that it is as unsafe to judge of an organism from the exclusive standpoint of its external characters as it is to judge of a book by the cover; for, apart from the check of breeding tests, it is impossible to say just which somatic characters are genetically significant, and which are not. Forms externally alike may be so unlike in germinal constitution as to be sexually incompatible; forms externally unlike may be readily crossed without any discernible diminution of fertility. “Who could have foreseen,” exclaims Bateson, “that the apple and the pear—so like each other that their botanical differences are evasive—could not be crossed together, though species of Antirrhinum (Snapdragon) so totally unlike each other as majus and molle can be hybridized, as Baur has shown, without a sign of impaired fertility?” (Heredity, Smithson. Inst. Rpt. for 1915, p. 370.) We cannot distinguish between alleged specific, and merely mutational (varietal), change, nor between hybridizations and factorial, chromosomal, or pseudo-, mutations, solely on the basis of such external characters as are preserved for us in fossils. It is impossible, therefore, to demonstrate trans-specific variation by any evidence that Palæontology can supply. The palæontologist (pace Osborn) is utterly incompetent to pass judgment on the problem of interspecific relationship. As Bateson remarks: “In discussing the physiological problem of interspecific relationship evidence of a more stringent character is now required; and a naturalist acquainted with genetical discoveries would be as reluctant to draw conclusions as to the specific relationship of a series of fossils as a chemist would be to pronounce on the nature of a series of unknown compounds from an inspection of them in a row of bottles.” (Science, April 17, 1922, p. 373.) “When the modern student of variation and heredity,” says T. H. Morgan, “looks over the different ‘continuous’ series, from which certain ‘laws’ and ‘principles’ have been deduced, he is struck by two facts: that the gaps, in some cases, are enormous as compared with the single changes with which he is familiar, and (what is more important) that they involve numerous parts in many ways. The geneticist says to the palæontologist, since you do not know, and from the nature of your case can never know, whether your differences are due to one change or to a thousand, you cannot with certainty tell us anything about the hereditary units which have made the process of evolution possible.” (Op. cit., pp. 26, 27.) And without accurate knowledge on this subject, we may add, there is no possibility of demonstrating specific change or genetic relationship in the case of any given fossil.

In our discussion of the third defect in the fossil “evidence,” allusion was made to a fourth, namely, its imperfect state of preservation. The stone record of bygone days has been so defaced by the metamorphism of rocks, by the solvent action of percolating waters, by erosion, weathering and other factors of destruction, that, like a faded manuscript, it becomes, even apart from its actual lacunae, exceedingly difficult to decipher. So unsatisfactory, indeed, is the condition of the partially obliterated facts that human curiosity, piqued at their baffling ambiguity, calls upon human imagination to supply what observation itself fails to reveal. Nor does the invitation remain unheeded. Romance hastens to the rescue of uncertain Science, with an impressive display of “reconstructed fossils,” and the hesitation of critical caution is superseded by the dogmatism of arbitrary assumption. Scattered fragments of fossilized bones are integrated into skeletons and clothed by the magic of creative fancy with an appropriate musculature and flesh, reënacting for us the marvelous vision of Ezekiel: “And the bones came together, each one to its joint. And I beheld and, lo, there were sinews upon them, and the flesh came upon them: and the skin was stretched over them.” (Chap. XXXVII, 7, 8.) “It is also true,” says Osborn (who, like Haeckel, evinces a veritable mania for “retouching” incomplete facts), “that we know the mode of origin of the human species; our knowledge of human evolution has reached a point not only where a number of links are thoroughly known but the characters of the missing links can be very clearly predicated.” (Science, Feb. 24, 1922.) We will not dispute his contention; for it is perfectly true, that, in each and every case, all the missing details can be so exactly predicated that the resulting description might well put to shame the account of a contemporary eyewitness. The only difficulty is that such predication is the fruit of pure imagination. Scientific reconstructions, whether in the literary, plastic, or pictorial, form, are no more scientific than historical novels are historical. Both are the outcome of a psychological weakness in the human makeup, namely, its craving for a “finished picture”—a craving, however, that is never gratified save at the expense of the fragmentary basis of objective fact.[7]

In calling into question, however, the scientific value of the so-called “scientific reconstruction,” so far as its pretensions to precision and finality are concerned, it is not our intention to discredit those tentative restorations based upon Cuvier’s Law of Correlation, provided they profess to be no more than provisional approximations. Many of the structural features of organisms are physiologically interdependent, and there is frequently a close correlation among organs and organ-systems, between which no causal connection or direct physiological dependence is demonstrable. In virtue of this principle, one structural feature may connote another, in which case it would be legitimate to supply by inference any missing structure implied in the actual existence of its respective correlative. But if any one imagines that the law of correlation enables a scientist to restore the lost integrity of fossil types with any considerable degree of accuracy and finality, he greatly overestimates the scope of the principle in question. At best it is nothing more than an empirical generalization, which must not be pressed to an extent unwarranted by the inductive process, that first established it. “Certain relations of structure,” says Bather, “as of cloven hoofs and horns with a ruminant stomach, were observed, but as Cuvier himself insisted, the laws based on such facts were purely empirical.” (Science, Sept. 17, 1920, p. 258.) The palæontologist, then, is justified in making use of correlation for the purpose of reconstructing a whole animal out of a few fragmentary remains, but to look for anything like photographic precision in such “restorations” of extinct forms is to manifest a more or less complete ignorance of the nature and scope of the empirical laws, upon which they are based.

The imprudence of taking these “reconstructions” of extinct forms too seriously, however, is inculcated not merely by theoretical considerations, but by experience as well. Even in the case of the mammoth, a comparatively recent form, whose skeletal remains had been preserved more completely and perfectly than those of other fossil types, the discovery of a complete carcass buried in the ice of the Siberian “taiga” on the Beresovka river showed the existing restorations to be false in important respects. All, without exception, stood in need of revision, proving, once and for all, the inadequacy of fossil remains as a basis for exact reconstruction. E. Pfizenmayer, a member of the investigating expedition, comments on the fact as follows: “In the light of our present knowledge of the mammoth, and especially of its exterior, the various existing attempts at a restoration need important corrections. Apart from the many fanciful sketches intended to portray the exterior of the animal, all the more carefully made restorations show the faults of the skeleton, hitherto regarded as typical, on which they are based, especially the powerful semicircular and upward-curved tusks, the long tail, etc.

“As these false conceptions of the exterior of the mammoth, both written and in the form of pictures, are contained in all zoölogical and palæontological textbooks, and even in scientific monographs, it seems necessary to construct a more nearly correct picture, based on our present knowledge. I have ventured on this task, because as a member of the latest expedition for mammoth remains, I was permitted not only to become acquainted with this newest find while still in its place of deposit and to take part in exhuming it, but also to visit the zoölogical museum of St. Petersburg, which is so rich in mammoth remains, for the purpose of studying the animal more in detail.” (Smithson. Inst. Rpt. for 1906, pp. 321, 322.) The example is but one of many, which serve to emphasize not merely the inadequacy of the generality of palæontological restorations, but also the extreme difficulty which the palæontologist experiences in interpreting aright the partially effaced record of a vanished past.

The fifth and most critical flaw in the fossil “evidence” for evolution is to be found in the anomalies of the actual distribution of fossils in time. It is the boast of evolutionary Palæontology that it is able to enhance the cogency of the argument from mere structural resemblance by showing, that, of two structurally allied forms, one is more ancient than the other, and may, therefore, be presumed to be ancestral to the later form. Antecedence in time is the sine qua non qualification of a credible ancestor, and, unless the relative priority of certain organic types, as compared with others, can be established with absolute certainty, the whole palæontological argument collapses, and the boast of evolutionary geology becomes an empty vaunt.

Whenever the appearance of a so-called annectant type is antedated by that of the two forms, which it is supposed to connect, this fact is, naturally, a deathblow to its claim of being the “common ancestor,” even though, from a purely morphological standpoint, it should possess all the requisites of an ancestral type. Commenting upon the statement that a certain genus “is a truly annectant form uniting the Melocrinidae and the Platycrinidae,” Bather takes exception as follows: “The genus in question appeared, so far as we know, rather late in the Lower Carboniferous, whereas both Platycrinidae and Melocrinidae were already established in Middle Silurian time. How is it possible that the far later form should unite these two ancient families? Even a mésalliance is inconceivable.” (Science, Sept. 17, 1920, p. 260.)

Certainty, therefore, with respect to the comparative antiquity of the fossiliferous strata is the indispensable presupposition of any palæontological argument attempting to show that there is a gradual approximation of ancient, to modern, types. Yet, of all scientific methods of reckoning, none is less calculated to inspire confidence, none less safeguarded from the abuses of subjectivism and arbitrary interpretation, than that by which the relative age of the sedimentary rocks is determined!

In order to date the strata of any given series with reference to one another, the palæontologist starts with the principle that, in an undisturbed area, the deeper sediments have been deposited at an earlier period than the overlying strata. Such a criterion, however, is obviously restricted in its application to local areas, and is available only at regions of outcrop, where a vertical section of the strata is visibly exposed. To trace the physical continuity, however, of the strata (if such continuity there be) from one continent to another, or even across a single continent, is evidently out of the question. Hence, to correlate the sedimentary rocks of a given region with those of another region far distant from the former, some criterion other than stratigraphy is required. To supply this want, recourse has been had to index fossils, which have now come into general use as age-markers and means of stratigraphical correlation, where the criterion of superposition is either absent or inapplicable. Certain fossil types are assumed to be infallibly indicative of certain stratigraphical horizons. In fact, when it comes to a decision as to the priority or posteriority of a given geological formation, index fossils constitute the court of last appeal, and even the evidences of actual stratigraphical sequence and of physical texture itself are always discounted and explained away, whenever they chance to conflict with the presumption that certain fossil forms are typical of certain geological periods. If, for example, the superposed rock contains fossils alleged to be typical of an “earlier” stratigraphic horizon than that to which the fossils of the subjacent rock belong, the former is pronounced to be “older,” despite the fact that the actual stratigraphic order conveys the opposite impression. “We still regard fossils,” says J. W. Judd, “as the ‘medals of creation,’ and certain types of life we take to be as truly characteristic of definite periods as the coins which bear the image and superscription of a Roman emperor or of a Saxon king.” (Cf. Smithson. Inst. Rpt. for 1912, p. 356.) Thus it comes to pass, in the last analysis, that fossils, on the one hand, are dated according to the consecutive strata, in which they occur, and strata, on the other hand, are dated according to the fossils which they contain.

Such procedure, if not actually tantamount to a vicious circle, is, to say the least, in imminent danger of becoming so. For, even assuming the so-called empirical generalization, that makes certain fossils typical of certain definitely-aged geological “formations,” to be based upon induction sufficiently complete and analytic to insure certainty, at least, in the majority of instances, and taking it for granted that we are dealing with a case, where the actual evidence of stratigraphy is not in open conflict with that of the index fossils, who does not see that such a system of chronology lends itself only too readily to manipulation of the most arbitrary kind, whenever the pet preconceptions of the evolutionary chronologist are at stake? How, then, can we be sure, in a given case, that a verdict based exclusively on the “evidence” of index fossils will be reliably objective? It is to be expected that the evolutionist will refrain from the temptation to give himself the benefit of every doubt? Will there not be an almost irresistible tendency on the part of the convinced transformist to revise the age of any deposit, which happens to contain fossils that, according to his theory, ought not to occur at the time hitherto assigned?

The citation of a concrete example will serve to make our meaning clear. A series of fresh-water strata occur in India known as the Siwalik beds. The formation in question was originally classed as Miocene. Later on, however, as a result, presumably, of the embarrassing discovery of the genus Equus among the fossils of the Upper Siwalik beds, Wm. Blanford saw fit to mend matters by distinguishing the Upper, from the Lower, beds and assigning the former (which contain fossil horses) to the Pliocene period. The title Miocene being restricted by this ingenious step to beds destitute of equine remains, namely the Nahun, or Lower Siwalik, deposits, all danger of the horse proving to be older than his ancestors was happily averted. A mere shifting of the conventional labels, apparently, was amply sufficient to render groundless the fear, to which Professor A. Sedgwick had given expression in the following terms: “The genus Equus appears in the upper Siwalik beds, which have been ascribed to the Miocene age.... If Equus really existed in the Upper Miocene, it was antecedent to some of its supposed ancestors.” (“Students’ Textbook of Zoölogy,” p. 599.) Evidently, the Horse must reconcile himself perforce to the pedigree assigned to him by the American Museum of Natural History; for he is to be given but scant opportunity of escaping it. This classic genealogy has already entailed far too great an expenditure of time, money and erudition to permit of any reconsideration; and should it chance, in the ironic perversity of things, that the Horse has been so inconsiderate as to leave indubitable traces of himself in any formation earlier than the Pliocene, it goes without saying that the formation in question will at once be dated ahead, in order to secure for the “ancestors” that priority which is their due. An elastic criterion like the index fossil is admirably adapted for readjustments of this sort, and the evolutionist who uses it need never fear defeat. The game he plays can never be a losing one, because he gives no other terms than: Heads I win, tails you lose.

In setting forth the foregoing difficulties, we have purposely refrained from challenging the cardinal dogma of orthodox palæontology concerning the unimpeachable time-value of index fossils as age-markers. The force of these considerations, therefore, must be acknowledged even by the most fanatical adherents of the aforesaid dogma. Our forbearance in this instance, however, must not be construed as a confession that the dogma in question is really unassailable. On the contrary, not only is it not invulnerable, but there are many and weighty reasons for rejecting it lock, stock, and barrel.

The palæontological dogma, to which we refer, is reducible to the following tenets: (1) The earth is swathed with fossiliferous strata, in much the same fashion that an onion is covered with a succession of coats, and these strata are universal over the whole globe, occurring always in the same invariable order and characterized not by any peculiar uniformity of external appearance, physical texture, or mineral composition, but solely by peculiar groups of fossil types, which enable us to distinguish between strata of different ages and to correlate the strata of one continent with their counterparts in another continent—“Even the minuter divisions,” says Scott, “the substages and zones of the European Jura, are applicable to the classification of the South American beds.” (“Introduction to Geology,” p. 681.) (2) In determining the relative age of a given geological formation, its characteristic fossils form the exclusive basis of decision, and all other considerations, whether lithological or stratigraphic, are subordinated to this—“The character of the rocks,” says H. S. Williams, “their composition or their mineral contents have nothing to do with settling the question as to the particular system to which the new rocks belong. The fossils alone are the means of correlation.” (“Geological Biology,” pp. 37, 38.)

To those habituated to the common notion that stratigraphical sequence is the foremost consideration in deciding the comparative age of rocks, the following statement of Sir Archibald Geikie will come as a distinct shock: “We may even demonstrate,” he avers, “that in some mountainous ground the strata have been turned completely upside down, if we can show that the fossils in what are now the uppermost layers ought properly to lie underneath those in the beds below them.” (“Textbook,” ed. of 1903, p. 837.) In fact, the palæontologist, H. A. Nicholson, lays it down as a general principle that, wherever the physical evidence (founded on stratigraphy and lithology) is at variance with the biological evidence (founded on the presence of typical fossil organisms), the latter must prevail and the former must be ignored: “It may even be said,” he tells us, “that in any case where there should appear to be a clear and decisive discordance between the physical and the palæontological evidence as to the age of a given series of beds, it is the former that is to be distrusted rather than the latter.” (“Ancient Life History of the Earth,” p. 40.)

George McCready Price, Professor of Geology at a denominational college in Kansas, devotes more than fifty pages of his recent work, “The New Geology” (1923), to an intensely destructive criticism of this dogma of the supremacy of fossil evidence as a means of determining the relative age of strata. To cite Price as an “authority” would, of course, be futile. All orthodox geologists have long since anathematized him, and outlawed him from respectable geological society. Charles Schuchert of Yale refers to him as “a fundamentalist harboring a geological nightmare.” (Science, May 30, 1924, p. 487.) Arthur M. Miller of Kentucky University speaks of him as “the man who, while a member of no scientific body and absolutely unknown in scientific circles, has ... had the effrontery to style himself a ‘geologist.’” (Science, June 30, 1922, pp. 702, 703.) Miller, however, is just enough to admit that he is well-informed on his subject, and that he possesses the gift of persuasive presentation. “He shows,” says Miller, “a wide familiarity with geological literature, quoting largely from the most eminent authorities in this country and in Europe. Any one reading these writings of Price, which possess a certain charm of literary style, and indicate on the part of the author a gift of popular presentation which makes one regret that it had not been devoted to a more laudable purpose, must constantly marvel at the character of mind of the man who can so go into the literature of the subject and still continue to hold such preposterous opinions.” (Loc. cit., p. 702.)

In the present instance, however, our interest centers, not on the unimportant question of his official status in geological circles, but exclusively on the objective validity of his argument against the chronometric value of the index fossil. All citations, therefore, from his work will be supported, in the sequel, by collateral testimony from other authors of recognized standing. It is possible, of course, to inject irrelevant issues. Price, for example, follows Sir Henry Howorth in his endeavor to substitute an aqueous catastrophe for the glaciation of the Quaternary Ice Age, and he adduces many interesting facts to justify his preference for a deluge. But this is neither here nor there; for we are not concerned with the merits of his “new catastrophism.” It is his opportune revival in modern form of the forgotten, but extremely effective, objection raised by Huxley and Spencer against the alleged universality of synchronously deposited fossiliferous sediments, that constitutes our sole preoccupation here. It is Price’s merit to have shown that, in the light of recently discovered facts, such as “deceptive conformities” and “overthrusts,” this objection is far graver than it was when first formulated by the authors in question.

Mere snobbery and abuse is not a sufficient answer to a difficulty of this nature, and we regret that men, like Schuchert, have replied with more anger than logic. The orthodox geologist seems unnecessarily petulant, whenever he is called upon to verify or substantiate the foundational principles of lithic chronology. One frequently hears him make the excuse that “geology has its own peculiar method of proof.” To claim exemption, however, from the universal criterions of criticism and logic is a subterfuge wholly unworthy of a genuine science, and, if Price insists on discussing a subject, which the orthodox geologist prefers to suppress, it is the latter, and not the former, who is really reactionary.

Price begins by stating the issue in the form of a twofold question: (1) How can we be sure, with respect to a given fauna (or flora), say the Cambrian, that at one time it monopolized our globe to the complete exclusion of all other typical faunas (or floras), say the Devonian, or the Tertiary, of which it is assumed that they could not, by any stretch of imagination, have been contemporaneous, on either land or sea, with the aforesaid “older” fauna (or flora)? (2) Do the formations (rocks containing fossils) universally occur in such a rigidly invariable order of sequence with respect to one another, as to warrant our being sure of the starting-point in the time-scale, or to justify us in projecting any given local order of succession into distant localities, for purposes of chronological correlation?

His response to the first of these questions constitutes what may be called an aprioristic refutation of the orthodox view, by placing the evolutionary palæontologist in the trilemma: (a) of making the awkward confession that, except within limited local areas, he has no means whatever of distinguishing between a geographical distribution of coëval fossil forms among various habitats and a chronological distribution of fossils among sediments deposited at different times; (b) or of denying the possibility of geographical distribution in the past, by claiming dogmatically that the world during Cambrian times, for example, was totally unlike the modern world, of which alone we have experimental knowledge, inasmuch as it was then destitute of zoölogical provinces, districts, zones, and other habitats peculiar to various types of fauna, so that the whole world formed but one grand habitat, extending over land and sea, for a limited group of organisms made up exclusively of the lower types of life; (c) or of reviving the discredited onion-coat theory of Abraham Werner under a revised biological form, which asserts that the whole globe is enveloped with fossiliferous rather than mineral strata, whose order of succession being everywhere the same enables us to discriminate with precision and certainty between cases of distribution in time and cases of distribution in space.

In his response to the second question, Professor Price adduces numerous factual arguments, which show that the invariable order of sequence postulated by the theory of the time-value of index fossils, not only finds no confirmation in the actual or concrete sequences of fossiliferous rocks, but is often directly contradicted thereby. “Older” rocks may occur above “younger” rocks, the “youngest” may occur in immediate succession to the “oldest,” Tertiary rocks may be crystalline, consolidated, and “old in appearance,” while Cambrian and even pre-Cambrian rocks sometimes occur in a soft, incoherent condition, that gives them the physical appearance of being as young as Pleistocene formations. These exceptions and objections to the “invariable order” of the fossiliferous strata accumulate from day to day, and it is only by means of Procrustean tactics of the most drastic sort that the facts can be brought into any semblance of harmony with the current dogmas, which base geology upon evolution rather than evolution upon geology.

Price, then, proposes for serious consideration the possibility that Cretaceous dinosaurs and even Tertiary mammals may have been living on the land at the same time that the Cambrian graptolites and trilobites were living in the seas. “Who,” he exclaims, “will have the hardihood, the real dogmatism to affirm in a serious way that Cambrian animals and seaweeds were for a long time the only forms of life existing anywhere on earth?” Should we, nevertheless, make bold enough to aver that for countless centuries a mere few of the lower forms of life monopolized our globe, as one universal habitat unpartitioned into particular biological provinces or zones, we are thereupon confronted with two equally unwelcome alternatives. We must either fly in the face of experience and legitimate induction by denying the existence in the past of anything analogous to our present-day geographical distribution of plants and animals into various biological provinces, or be prepared to show by what infallible criterion we are enabled to distinguish between synchronously deposited formations indicative of a geographical distribution according to regional diversity, and consecutively deposited formations indicative of comparative antiquity.

The former alternative does not merit any consideration whatever. The latter, as we shall presently see, involves us in an assumption, for which no defense either aprioristic or factual is available. We can, indeed, distinguish between spatial, and temporal, distribution within the narrow limits of a single locality by using the criterion of superposition; for in regions of outcrop, where one sedimentary rock overlies another, the obvious presumption is that the upper rock was deposited at a later date than the lower rock. But the criterion of superposition is not available for the correlation of strata in localities so distant from each other that no physical evidence of stratigraphic continuity is discernible. Moreover the induction, which projects any local order of stratigraphical sequence into far distant localities on the sole basis of fossil taxonomy, is logically unsound and leads to conclusions at variance with the actual facts. Hence the alleged time-value of index fossils becomes essentially problematic, and affords no basis whatever for scientific certainty.

As previously stated, the sequence of strata is visible only in regions of outcrop, and nowhere are we able to see more than mere parts of two or, at most, three systems associated together in a single locality. Moreover, each set of beds is of limited areal extent, and the limits are frequently visible to the eye of the observer. In any case, their visible extent is necessarily limited. It is impossible, therefore, to correlate the strata of one continent with those of another continent by tracing stratigraphic continuity. Hence, in comparing particular horizons of various ages and in distinguishing them from other horizons over large areas, we are obliged to substitute induction for direct observation. Scientific induction, however, is only valid when it rests upon some universal uniformity or invariable sequence of nature. Hence, to be specific, the assumption that the time-scale based on the European classification of fossiliferous strata is applicable to the entire globe as a whole, is based on the further assumption that we are sure of the universality of fossiliferous stratification over the face of the earth, and that, as a matter of fact, fossils are always and everywhere found in the same order of invariable sequence.

But this is tantamount to reviving, under what Spencer calls “a transcendental form,” the exploded “onion-coat” hypothesis of Werner (1749-1817). Werner conceived the terrestrial globe as encircled with successive mineral envelopes, basing his scheme of universal stratification upon that order of sequence among rocks, which he had observed within the narrow confines of his native district in Germany. His hypothesis, after leading many scientists astray, was ultimately discredited and laughed out of existence. For it finally became evident to all observers that Werner’s scheme did not fit the facts, and men were able to witness with their own eyes the simultaneous deposition, in separate localities, of sediments which differed radically in their mineral contents and texture. Thus it came to pass that this classification of strata according to their mineral nature and physical appearance lost all value as an absolute time-scale, while the theory itself was relegated to the status of a curious and amusing episode in the history of scientific fiascos.

Thanks, however, to Wm. Smith and to Cuvier, the discarded onion-coat hypothesis did not perish utterly, but was rehabilitated and bequeathed to us in a new and more subtle form. Werner’s fundamental idea of the universality of a given kind of deposit was retained, but his mineral strata were replaced by fossiliferous strata, the lithological onion-coats of Werner being superseded by the biological onion-coats of our modern theory. The geologist of today discounts physical appearance, and classifies strata according to their fossil, rather than their mineral, contents, but he stands committed to the same old postulate of universal deposits. He has no hesitation in synchronizing such widely-scattered formations as the Devonian deposits of New York State, England, Germany, and South America. He pieces them all together as parts of a single system of rocks. He has no misgiving as to the universal applicability of the European scheme of stratigraphic classification, but assures us, in the words of the geologist, Wm. B. Scott, that: “Even the minuter divisions, the subdivisions and zones of the European Jura, are applicable to the classification of the South American beds.” (“Introduction to Geology,” p. 681f.) The limestone and sandstone strata of Werner are now things of the past, but, in their stead, we have, to quote the criticism of Herbert Spencer, “groups of formations which everywhere succeed each other in a given order, and are severally everywhere of the same age. Though it may not be asserted that these successive systems are universal, yet it seems to be tacitly assumed that they are so.... Though probably no competent geologist would contend that the European classification of strata is applicable to the globe as a whole, yet most, if not all geologists, write as though it were so.... Must we not say that though the onion-coat hypothesis is dead, its spirit is traceable, under a transcendental form, even in the conclusions of its antagonists.” (“Illustrations of Universal Progress,” pp. 329-380, ed. of 1890.)

But overlooking, for the moment, the mechanical absurdity involved in the notion of a regular succession of universal layers of sediment, and conceding, for the sake of argument, that the substitution of fossiliferous, for lithological, strata may conceivably have remedied the defects of Werner’s geological time-scale, let us confine ourselves to the one question, which, after all, is of prime importance, whether, namely, without the aid of Procrustean tactics, the actual facts of geology can be brought into alignment with the doctrine of an invariable order of succession among fossil types, and its sequel, the intrinsic time-value of index fossils. The question, in other words, is whether or not a reliable time-scale can be based on the facts of fossiliferous stratification as they are observed to exist in the concrete. Price’s answer is negative, and he formulates several empirical laws to express the concrete facts, on which he bases his contention. The laws and facts to which he appeals may be summarized as follows:

1. The concrete facts of geology do not warrant our singling out any fossiliferous deposit as unquestionably the oldest, and hence we have no reliable starting-point for our time-scale, because:

(a) We may lay it down as an empirical law that “any kind of fossiliferous rock (even the ‘youngest’), that is, strata belonging to any of the systems or other subdivisions, may rest directly upon the Archæan or primitive crystalline rocks, without any other so-called ‘younger’ strata intervening; also these rocks, Permian, Cretaceous, Tertiary, or whatever thus reposing directly on the Archæan may be themselves crystalline or wholly metamorphic in texture. And this applies not alone to small points of contact, but to large areas.”

(b) Conversely: any kind of fossiliferous strata (even the “oldest”) may not only constitute the surface rocks over wide areas,[8] but may consist of loose, unconsolidated materials, thus in both position and texture resembling the “late” Tertiaries or the Pleistocene—“In some regions, notably in the Baltic province and in parts of the United States,” says John Allen Howe, alluding to the Cambrian rocks around the Baltic Sea and in Wisconsin, “the rocks still retain their original horizontality of deposition, the muds are scarcely indurated, and the sands are incoherent.” (Encycl. Brit., vol. V, p. 86.)

A large number of striking instances are cited by Price to substantiate the foregoing rule and its converse. The impression left is that not only is the starting-point of the time-scale in doubt, but that, if we were to judge the age of the rocks by their physical appearance and position, we could not accept the conventional verdicts of modern geology, which makes fossil evidence prevail over every other consideration.

2. When two contiguous strata are parallel to each other, and there is no indication of disturbance in the lower bed, nor any evidence of erosion along the plane of contact, the two beds are said to exhibit conformity, and this is ordinarily interpreted by geologists as a sign that the upper bed has been laid down in immediate sequence to the lower, and that there has been a substantial continuity of deposition, with no long interval during which the lower bed was exposed as surface to the agents of erosion. When such a conformity exists, as it frequently does, between a “recent” stratum, above, and what is said (according to the testimony of the fossils) to be a very “ancient” stratum, below, and though the two are so alike lithologically as to be mistaken for one and the same formation, nevertheless, such a conformity is termed a “non-evident disconformity,” or “deceptive conformity,” implying that, inasmuch as the “lost interval,” representing, perhaps, a lapse of “several million years,” is entirely unrecorded by any intervening deposition, or any erosion, or any disturbance of the lower bed, we should not have suspected that so great a hiatus had intervened, were it not for the testimony of the fossils. Price cites innumerable examples, and sums them up in the general terms of the following empirical law: “Any sort of fossiliferous formation may occur on top of any other ‘older’ fossiliferous formation, with all the physical evidences of perfect conformity, just as if these alleged incongruous or mismated formations had in reality followed one another in quick succession.”

A quotation from Schuchert’s “Textbook of Geology,” (1920), may be given by way of illustration: “The imperfection,” we read, “of the geologic column is greatest in the interior of North America and more so in the north than in the south. This imperfection is in many places very marked, since an entire period or several periods may be absent. With such great breaks in the local sections the natural assumption is that these gaps are easily seen in the sequence of the strata, but in many places the beds lie in such perfect conformity upon one another that the breaks are not noticeable by the eye and can be proved to exist only by the entombed fossils on each side of a given bedding plane.... Stratigraphers are, as a rule, now fully aware of the imperfections in the geologic record, but the rocks of two unrelated formations may rest upon each other with such absolute conformability as to be completely deceptive. For instance, in the Bear Grass quarries at Louisville, Ky., a face of limestone is exposed in which the absolute conformability of the beds can be traced for nearly a mile, and yet within 5 feet of vertical thickness is found a Middle Silurian coral bed overlain by another coral zone of Middle Devonian. The parting between these two zones is like that between any two limestone beds, but this insignificant line represents a stratigraphic hiatus the equivalent of the last third of Silurian and the first of Devonian time. But such disconformities are by no means rare, in fact are very common throughout the wide central basin area of North America.” (Op. cit., II, pp. 586-588.)

In such cases, the stratigraphical relations give no hint of any enormous gap at the line of contact. On the contrary, there is every evidence of unbroken sequence, and the physical appearances are as if these supposed “geological epochs” had never occurred in the localities, of which there is question. Everything points to the conclusion that the alleged long intervals of time between such perfectly conformable, and, often, lithologically identical, formations are a pure fiction elaborated for the purpose of bolstering up the dogma of the universal applicability of the European classification of fossiliferous rocks. Why not take the facts as we find them? Why resort to tortuous explanations for the mere purpose of saving an arbitrary time-scale? Why insist on a definite time-value for fossils, when it drives us to the extremity of discrediting the objective evidence of physical facts in deference to the preconceptions of orthodox geology? Were it not for theoretical considerations, these stratigraphic facts would be taken at their face value, and the need of saving the reputation of the fossil as an infallible time index is not sufficiently imperative to warrant so drastic a revision of the physical evidence.

3. The third class of facts militating against the time-value of index fossils, are what Price describes as “deceptive conformities turned upside down,” and what orthodox geology tries to explain away as “thrusts,” “thrust faults,” “overthrusts,” “low-angle faulting,” etc.[9] In instances of this kind we find the accepted order of the fossiliferous strata reversed in such a way that the “younger” strata are conformably overlain by “older” strata, and the “older” strata are sometimes interbedded between “younger” strata. “In many places all over the world,” says Price, “fossils have been found in a relative order which was formerly thought to be utterly impossible. That is, the fossils have been found in the ‘wrong’ order, and on such a scale that there can be no mistake about it. For when an area 500 miles long and from 20 to 50 miles wide is found with Palæozoic rocks on top, or composing the mountains, and with Cretaceous beds underneath, or composing the valleys, and running under these mountains all around, as in the case of the Glacier National Park and the southern part of Alberta, the old notion about the exact and invariable order of the fossils has to be given up entirely.”

Price formulates his third law as follows: “Any fossiliferous formation, ‘old’ or ‘young,’ may occur conformably on any other fossiliferous formation, ‘younger’ or ‘older.’” The corollary of this empirical law is that we are no longer justified in regarding any fossils as intrinsically older than other fossils, and that our present classification of fossiliferous strata has a taxonomic, rather than a historical, value.

Low-angle faulting is the phenomenon devised by geologists to meet the difficulty of “inverted sequence,” when all other explanations fail. Immense mountain masses are said to have been detached from their roots and pushed horizontally over the surface (without disturbing it in the least), until they came finally to rest in perfect conformity upon “younger” strata, so that the plane of slippage ended by being indistinguishable from an ordinary horizontal bedding plane. These gigantic “overthrusts” or “thrust faults” are a rather unique phenomenon. Normal faulting is always at a high angle closely approaching the vertical, but “thrust faults” are at a low angle closely approximating the horizontal, and there is enormous displacement along the plane of slippage. The huge mountain masses are said to have been first lifted up and then thrust horizontally for vast distances, sometimes for hundreds of miles, over the face of the land, being thus pushed over on top of “younger” rocks, so as to repose upon the latter in a relation of perfectly conformable superposition. R. G. McConnell, of the Canadian Survey, comments on the remarkable similarity between these alleged “thrust planes” and ordinary stratification planes, and he is at a loss to know why the surface soil was not disturbed by the huge rock masses which slid over it for such great distances. Speaking of the Bow River Gap, he says: “The fault plane here is nearly horizontal, and the two formations, viewed from the valley appear to succeed one another conformably,” and then having noted that the underlying Cretaceous shales are “very soft,” he adds that they “have suffered little by the sliding of the limestones over them.” (An. Rpt. 1886, part D., pp. 33, 34, 84.) Credat Iudaeus Apella, non ego!

Schuchert describes the Alpine overthrust as follows: “The movement was both vertical and thrusting from the south and southeast, from the southern portion of Tethys, elevating and folding the Tertiary and older strata of the northern areas of this mediterranean into overturned, recumbent, and nearly horizontal folds, and pushing the southern or Lepontine Alps about 60 miles to the northward into the Helvetic region. Erosion has since carved up these overthrust sheets, leaving remnants lying on foundations which belong to a more northern portion of the ancient sea. Most noted of these residuals of overthrust masses is the Matterhorn, a mighty mountain without roots, a stranger in a foreign geologic environment,” (Pirsson & Schuchert’s “Textbook of Geology,” 1920, II, p. 924.)

With such a convenient device as the “overthrust” at his disposal, it is hard to see how any possible concrete sequence of fossiliferous strata could contradict the preconceptions of an evolutionary geologist. The hypotheses and assumptions involved, however, are so tortuous and incredible, that nothing short of fanatical devotion to the theory of transformism can render them acceptable. “Examples,” says Price, “of strata in the ‘wrong’ order were first reported from the Alps nearly half a century ago. Since that time, whole armfuls of learned treatises in German, in French, and in English have been written to explain the wonderful conditions there found. The diagrams that have been drawn to account for the strange order of the strata are worthy to rank with the similar ones by the Ptolemaic astronomers picturing the cycles and epicycles required to explain the peculiar behavior of the heavenly bodies in accordance with the geocentric theory of the universe then prevailing.... In Scandinavia, a district some 1,120 miles long by 80 miles wide is alleged to have been pushed horizontally eastward ‘at least 86 miles.’ (Schuchert.) In Northern China, one of these upside down areas is reported by the Carnegie Research Expedition to be 500 miles long.” (“The New Geology,” 1923, pp. 633, 634.)

Nor are the epicyclic subterfuges of the evolutionary geologist confined to “deceptive conformities” and “overthrusts.” His inventive genius has hit upon other methods of explaining away inconvenient facts. When, for example, “younger” fossils are found interbedded with “older” fossils, and the discrepancy in time is not too great, he rids himself of the difficulty of their premature appearance by calling them a “pioneer colony.” Similarly, when a group of “characteristic” fossils occur in one age, skip another “age,” and recur in a third, he recognizes the possibility of “recurrent faunas,” some of these faunas having as many as five successive “recurrences.” Clearly, the assumption of gradual approximation and the dogma that the lower preceded the higher forms of life are things to be saved at all costs, and it is a foregone conclusion that no facts will be suffered to conflict with these irrevisable articles of evolutionary faith. “What is the use,” exclaims Price, “of pretending that we are investigating a problem of natural science, if we already know beforehand that the lower and more generalized forms of animals and plants came into existence first, and the higher and the more specialized came only long afterwards, and that specimens of all these successive types have been pigeonholed in the rocks in order to help us illustrate this wonderful truth?” (Op. cit., pp. 667, 668.)

The predominance of extinct species in certain formations is said to be an independent argument of their great age. Most of the species of organisms found as fossils in Cambrian, Ordovician, and Silurian rocks are extinct, whereas modern types abound in Cretaceous and Tertiary rocks. Hence it is claimed that the former must be vastly older than the latter. But this argument gratuitously assumes the substantial perfection of the stone record of ancient life and unwarrantedly excludes the possibility of a sudden impoverishment of the world’s flora and fauna as the result of a sweeping catastrophe, of which our present species are the fortunate survivors. Now the fact that certain floras and faunas skip entire systems of rocks to reappear only in later formations is proof positive that the record of ancient life is far from being complete, and we have in the abundant fossil remains of tropical plants and animals, found in what are now the frozen arctic regions, unmistakable evidence of a sudden catastrophic change by which a once genial climate “was abruptly terminated. For carcasses of the Siberian elephants were frozen so suddenly and so completely that the flesh has remained untainted.” (Dana.) Again, the mere fact of extinction tells us nothing about the time of the extinction. For this we are obliged to fall back on the index fossil whose inherent time-value is based on the theory of evolution and not on stratigraphy. Hence the argument from extinct species is not an independent argument.

To sum up, therefore, the aprioristic evolutional series of fossils is not a genuine time-scale. The only safe criterion of comparative age is that of stratigraphic superposition, and this is inapplicable outside of limited local areas.[10] The index fossil is a reliable basis for the chronological correlation of beds only in case one is already convinced on other grounds of the actuality of evolution, but for the unbiased inquirer it is destitute of any inherent time-value. In other words, we can no longer be sure that a given formation is old merely because it happens to contain Cambrian fossils, nor that a rock is young merely because it chances to contain Tertiary fossils. Our present classification of rocks according to their fossil contents is purely arbitrary and artificial, being tantamount to nothing more than a mere taxonomical classification of the forms of ancient life on our globe, irrespective of their comparative antiquity. This scheme of classification is, indeed, universally applicable, and places can usually be found in it for new fossiliferous strata, whenever and wherever discovered. Its universal applicability, however, is due not to any prevalent order of invariable sequence among fossiliferous strata, but solely to the fact that the laws of biological taxonomy and ecology are universal laws which transcend spatial and temporal limitation. If a scheme of taxonomy is truly scientific, all forms of life, whether extant or extinct, will fit into it quite readily.

The anomalies of spatial distribution constitute a sixth difficulty for transformistic palæontology. In constructing a phylogeny the most diverse and widely-separated regions are put under tribute to furnish the requisite fossils, no heed being paid to what are now at any rate impassable geographical barriers, not to speak of the climatic and environmental limitations which restrict the migrations of non-cosmopolitan species within the boundaries of narrow habitats. Hypothetical lineages of a modern form of life are frequently constructed from fossil remains found in two or more continents separated from one another by immense distances and vast oceanic expanses. When taxed with failure to plausibleize this procedure, the evolutionist meets the difficulty by hypothecating wholesale and devious migrations to and fro, and by raising up alleged land bridges to accommodate plants and animals in their suppositional migrations from one continent to another, etc.

The European horse, with his so-called ancestry interred, partly in the Tertiary deposits of Europe, but mostly in those of North America, is a typical instance of these anomalies in geographical distribution. It would, of course, be preposterous to suppose that two independent lines of descent could have fortuitously terminated in the production of one and the same type, namely, the genus Equus. Moreover, to admit for a moment that the extinct American Equus and the extant European Equus had converged by similar stages from distinct origins would be equivalent, as we have seen, to a surrender of the basic postulate that structural similarity rests on the principle of inheritance. Nothing remains, therefore, but to hypothecate a Tertiary land bridge between Europe and North America.

Modern geologists, however, are beginning to resent these arbitrary interferences with their science in the interest of biological theories. Land bridges, they rightly insist, should be demonstrated by means of positive geological evidence and not by the mere exigencies of a hypothetical genealogy. Whosoever postulates a land bridge between continents should be able to adduce solid reasons, and to assign a mechanism capable of accomplishing the five-mile uplift necessary to bring a deep-sea bottom to the surface of the hydrosphere. Such an idea is extravagant and not to be easily entertained in our day, when geologists are beginning to understand the principle of isostasy. To-day, the crust of the earth, that is, the entire surface of the lithosphere, is conceived as being constituted of earth columns, all of which rest with equal weight upon the level of complete compensation, which exists at a depth of some 76 miles below land surfaces. At this depth viscous flows and undertows of the earth take place, compensating all differences of gravitational stress. Hence the materials constituting a mountain column are thought to be less dense than those constituting the surrounding lowland columns, and for this reason the mountains are buoyed up above the surrounding landscape. The columns under ocean bottoms, on the contrary, are thought to consist of heavy materials like basalt, which tend to depress the column. To raise a sea floor, therefore, some means of producing a dilatation of these materials would have to be available. Arthur B. Coleman called attention to this difficulty in his Presidential Address to the Geological Society of America (December 29, 1915), and we cannot do better than quote his own statement of the matter here:

“Admitting,” he says, “that in the beginning the lithosphere bulged up in places, so as to form continents, and sagged in other places, so as to form ocean beds, there are interesting problems presented as to the permanence of land and seas. All will admit marginal changes affecting large areas, but these encroachments of the sea on the continents and the later retreats may be of quite a subordinate kind, not implying an interchange of deep-sea bottoms and land surfaces. The essential permanence of continents and oceans has been firmly held by many geologists, notably Dana among the older ones, and seems reasonable; but there are geologists, especially palæontologists, who display great recklessness in rearranging land and sea. The trend of a mountain range, or the convenience of a running bird, or a marsupial afraid to wet his feet seems sufficient warrant for hoisting up any sea bottom to connect continent with continent. A Gondwana Land arises in place of an Indian Ocean and sweeps across to South America, so that a spore-bearing plant can follow up an ice age; or an Atlantis ties New England to Old England to help out the migrations of a shallow-water fauna; or a ‘Lost Land of Agulhas’ joins South Africa and India.

“It is curious to find these revolutionary suggestions made at a time when geodesists are demonstrating that the earth’s crust over large areas, and perhaps everywhere, approaches a state of isostatic equilibrium, and that isostatic compensation is probably complete at a depth of only 76 miles” ... and (having noted the difference of density that must exist between the continental, and submarine, earth columns) Coleman would have us bear in mind “that to transform great areas of sea bottom into land it would be necessary either to expand the rock beneath by several per cent or to replace heavy rock, such as basalt, by lighter materials, such as granite. There is no obvious way in which the rock beneath a sea bottom can be expanded enough to lift it 20,000 feet, as would be necessary in parts of the Indian Ocean, to form a Gondwana land; so one must assume that light rocks replace heavy ones beneath a million square miles of ocean floor. Even with unlimited time, it is hard to imagine a mechanism that could do the work, and no convincing geological evidence can be brought forward to show that such a thing ever took place.... The distribution of plants and animals should be arranged for by other means than by the wholesale elevation of ocean beds to make dry land bridges for them.” (Smithson. Inst. Rpt. for 1916, pp. 269-271.)

A seventh anomaly of palæontological phylogeny is what may be described as contrariety of direction. We are asked to believe, for example, that in mammals racial development resulted in dimensional increase. The primitive ancestor of mammoths, mastodons, and elephants is alleged to have been the Moeritherium, “a small tapirlike form, from the Middle Eocene Qasr-el-Sagha beds of the Fayûm in Egypt.... Moeritherium measured about 3½ feet in height.” (Lull: Smithson. Inst. Rpt. for 1908, pp. 655, 656.) The ancestor of the modern horse, we are told, was “a little animal less than a foot in height, known as Eohippus, from the rocks of the Eocene age.” (Woodruff: “Foundations of Biology,” p. 361.) In the case of insects, on the other hand, we are asked to believe the exact reverse, namely, that racial development brought about dimensional reduction. “In the middle of the Upper Carboniferous periods,” says Anton Handlirsch, “the forest swamps were populated with cockroaches about as long as a finger, dragonfly-like creatures with a wing spread of about 2½ feet, while insects that resemble our May flies were as big as a hand.” (“Die fossilen Insekten, und die Phylogenie der recenten Formen,” 1908, L. c., p. 1150.) Contrasting one of these giant palæozoic dragonflies, Meganeura monyi Brongn., with the largest of modern dragonflies, Aeschna grandis L., Chetverikov exclaims with reference to the latter: “What a pitiful pigmy it is and its specific name (grandis) sounds like such a mockery.” (Smithson. Inst. Rpt. for 1918, p. 446.) Chetverikov, it is true, proposes a teleological reason for this progressive diminution, but the fact remains that for dysteleological evolutionism, which dispenses with the postulate of a Providential coördination and regulation of natural agencies, this diminuendo of the “evolving” insects stands in irreconcilable opposition to the crescendo of the “evolving” mammals, and constitutes a difficulty which a purely mechanistic philosophy can never surmount.

Not to prolong excessively this already protracted enumeration of discrepancies between fossil fact and evolutionary assumption, we shall mention, as an eighth and final difficulty, the indubitable persistence of unchanged organic types from the earliest geological epochs down to the present time. This phenomenon is all the more wonderful in view of the fact that the decision as to which are to be the “older” and which the “younger” strata rests with the evolutionary geologist, who is naturally disinclined to admit the antiquity of strata containing modern types, and whose position as arbiter enables him to date formations aprioristically, according to the exigencies of the transformistic theory. Using, as he does, the absence of modern types as an express criterion of age, and having, as it were, his pick among the various fossiliferous deposits, one would expect him to be eminently successful in eliminating from the stratigraphic groups selected for senior honors all strata containing fossil types identical with modern forms. Since, however, even the most ingenious sort of geological gerrymandering fails to make this elimination complete, we must conclude that the evidence for persistence of type is inescapable and valid under any assumption.

When we speak of persistent types, we mean generic and specific, rather than phyletic, types, although it is assuredly true that the persistence of the great phyla, from their abrupt and contemporaneous appearance in Cambrian and pre-Cambrian rocks down to the present day, constitutes a grave difficulty for progressive evolution in general and monophyletic evolution in particular. All the great invertebrate types, such as the protozoa, the annelida, the brachiopoda, and large crustaceans called eurypterids, are found in rocks of the Proterozoic group, despite the damaged condition of the Archæan record, while in the Cambrian they are represented by a great profusion of forms. “The Lower Cambrian species,” says Dana, “have not the simplicity of structure that would naturally be looked for in the earliest Palæozoic life. They are perfect of their kind and highly specialized structures. No steps from simple kinds leading up to them have been discovered; no line from the protozoans up to corals, echinoderms, or worms, or from either of these groups up to brachiopods, mollusks, trilobites, or other crustaceans. This appearance of abruptness in the introduction of Cambrian life is one of the striking facts made known by geology.” (“Manual,” p. 487.) Thus, as we go backward in time, we find the great organic phyla retaining their identity and showing no tendency to converge towards a common origin in one or a few ancestral types. For this reason, as we shall see presently, geologists are beginning to relegate the evolutionary process to unknown depths below the explored portion of the “geological column.” What may lurk in these unfathomed profundities, it is, of course, impossible to say, but, if we are to judge by that part of the column which is actually exposed to view, there is no indication whatever of a steady progression from lower, to higher, degrees of organization, and it takes all the imperturbable idealism of a scientific doctrinaire to discern in such random, abrupt, and unrelated “origins” any evidence of what Blackwelder styles “a slow but steady increase in complexity of structure and in function.” (Science, Jan. 27, 1922, p. 90.)

But, while the permanence of phyletic types excludes progress, that of generic and specific types excludes change, and hence it is in the latter phenomenon, especially, that the theory of transformism encounters a formidable difficulty. Palæobotany furnishes numerous examples of the persistence of unchanged plant forms. Ferns identical with the modern genus Marattia occur in rocks of the Palæozoic group. Cycads indistinguishable from the extant genera Zamia and Cycas are found in strata belonging to the Triassic system, etc., etc.

The same is true of animal types. In all the phyla some genera and even species have persisted unchanged from the oldest strata down to the present day. Among the Protozoa, for example, we have the genus Globigerina (one of the Foraminifera), some modern species of which are identical with those found in the Cretaceous. To quote the words of the Protozoologist, Charles A. Kofoid: “The Protozoa are found in the oldest fossiliferous rocks and the genera of Radiolaria therein conform rather closely to genera living today, while the fossil Dinoflagellata of the flints of Delitzsch are scarcely distinguishable from species living in the modern seas. The striking similarities of the most ancient fossil Protozoa to recent ones afford some ground for the inference that the Protozoa living today differ but little from those when life was young.” (Science, April 6, 1923, p. 397.)

The Metazoa offer similar examples of persistence. Among the Cœlenterata, we have the genus Springopora, whose representatives from the Carboniferous limestones closely resemble some of the present-day reef builders of the East Indies. Species of the brachiopod genera Lingula and Crania occurring in the Cambrian rocks are indistinguishable from species living today, while two other modern genera of the Brachiopoda, namely, Rhynchonella and Discina, are represented among the fossils found in Mesozoic formations. Terebratulina striata, a fossil species of brachiopod occurring in the rocks belonging to the Cretaceous system, is identical with our modern species Terebratulina caput serpentis. Among the Mollusca such genera as Arca, Nucula, Lucina, Astarte, and Nautilus have had a continuous existence since the Silurian, while the genera Lima and Pecten can be traced to the Permian. One genus Pleurotomaria goes back to pre-Cambrian times. As to Tertiary fossils, Woods informs us that “in some of the later Cainozoic formations as many as 90 per cent of the species of mollusks are still living.” (“Palæontology,” 1st ed., p. 2.) Among the Echinodermata, two genera, Cidaris (a sea urchin) and Pentacrinus (a crinoid) may be mentioned as being persistent since the Triassic (“oldest” system of the Mesozoic group). Among the Arthropoda, the horseshoe crab Limulus polyphemus has had a continuous existence since the Lias (i.e. the lowest series of the Jurassic system). Even among the Vertebrata we have instances of persistence. The extant Australian genus Ceratodus, a Dipnoan, has been in existence since the Triassic. Among the fossils of the Jurassic (middle system of the Mesozoic group), Sharks, Rays, and Chimaeroids occur in practically modern forms, while some of the so-called “ganoids” are extremely similar to our present sturgeons and gar pikes—“Some of the Jurassic fishes approximate the teleosts so closely that it seems arbitrary to call them ganoids.” (Scott.)

The instances of persistence enumerated above are those acknowledged by evolutionary palæontologists themselves. This list could be extended somewhat by the addition of several other examples, but even so, it would still be small and insufficient to tip the scales decisively in favor of fixism. On the other hand, we must not forget that the paucity of this list is due in large measure to the fact that our present method of classifying fossiliferous strata was deliberately framed with a view to excluding formations containing modern types from the category of “ancient” beds. Moreover, orthodox palæontology has minimized the facts of persistence to an extent unwarranted even by its own premises. As the following considerations indicate, the actual number of persistent types is far greater, even according to the evolutionary time-scale, than the figure commonly assigned.

First of all, we must take into account the deplorable, if not absolutely dishonest, practice, which is in vogue, of inventing new names for the fossil duplicates of modern species, in order to mask or obscure an identity which conflicts with evolutionary preconceptions. When a given formation fails to fit into the accepted scheme by reason of its fossil anachronisms, or when, to quote the words of Price, “species are found in kinds of rock where they are not at all expected, and where, according to the prevailing theories, it is quite incredible that they should be found ... the not very honorable expedient is resorted to of inventing a new name, specific or even generic, to disguise and gloss over the strange similarity between them and the others which have already been assigned to wholly different formations.” (“The New Geology,” p. 291.) The same observation is made by Heilprin. “It is practically certain,” says the latter, “that numerous forms of life, exhibiting no distinctive characters of their own, are constituted into distinct species for no other reason than that they occur in formations widely separated from those holding their nearest kin.” (“Geographical and Geological Distribution of Animals,” pp. 183, 184.) An instance of this practice occurs in the foregoing list, where a fossil brachiopod identical with a modern species receives the new specific name “striata.” Its influence is also manifest in the previously quoted apology of Scott for calling teleost-like fish “ganoids.”

We must also take into account the imperfection of the fossil record, which is proved by the fact that most of the acknowledged “persistent types” listed above “skip” whole systems and even groups of “later” rocks (which are said to represent enormous intervals of time), only to reappear, at last, in modern times. It is evident that their existence has been continuous, and yet they are not represented in the intervening strata. Clearly, then, the fossil record is imperfect, and we must conclude that many of our modern types actually did exist in the remote past, without, however, leaving behind any vestige of their former presence.

Again, we must frankly confess our profound ignorance with respect to the total number and kinds of species living in our modern seas. Hence our conventional distinction between “extinct” and “extant” species has only a provisory value. Future discoveries will unquestionably force us to admit that many of the species now classed as “extinct” are in reality living forms, which must be added to our list of “persistent types.” “It is by no means improbable,” says Heilprin, “that many of the older genera, now recognized as distinct by reason of our imperfect knowledge concerning their true relationships, have in reality representatives in the modern sea.” (Op. cit. pp. 203, 204.)

Finally, the whole of our present taxonomy of plants and animals, both living and fossil, stands badly in need of revision. Systematists, as we have seen in the second chapter, base their classifications mainly on what they regard as basic or homologous structures, in contradistinction to superficial or adaptive characters. Both kinds of structure, however, are purely somatic, and somatic characters, as previously observed, are not, by themselves, a safe criterion for discriminating between varieties and species. In the light of recent genetical research, we cannot avoid recognizing that there has been far too much “splitting” of organic groups on the basis of differences that are purely fluctuational, or, at most, mutational. Moreover, the distinction between homologous and adaptive structures is often arbitrary and largely a matter of personal opinion, especially when numerous specimens are not available. What the “Cambridge Natural History” says in allusion to the Asteroidea is of general application. “While there is considerable agreement,” we read, “amongst authorities as to the number of families, or minor divisions of unequivocal relationship, to be found in the class Asteroidea, there has been great uncertainty both as to the number and limits of the orders into which the class should be divided, and also as to the limits of the various species. The difficulty about the species is by no means confined to the group Echinodermata; in all cases where the attempt is made to determine species by an examination of a few specimens of unknown age there is bound to be uncertainty; the more so, as it becomes increasingly evident that there is no sharp line to be drawn between local varieties and species. In Echinodermata, however, there is the additional difficulty that the acquisition of ripe genital cells does not necessarily mark the termination of growth; the animals can continue to grow and at the same time slightly alter their characters. For this reason many of the species described may be merely immature forms....

“The disputes, however, as to the number of orders included in the Asteroidea proceed from a different cause. The attempt to construct detailed phylogenies involves the assumption that one set of structures, which we take as the mark of the class, has remained constant, whilst the others which are regarded as adaptive, may have developed twice or thrice. As the two sets of structures are about of equal importance it will be seen to what an enormous extent the personal equation enters in the determination of these questions.” (Op. cit., vol. I, pp. 459, 460.)

In dealing with fossil forms, these difficulties of the taxonomist are intensified: (1) by the sparse, badly-preserved, and fragmentary character of fossil remains; (2) by the fact that here breeding experiments are impossible, and hence the diagnosis based on external characters cannot be supplemented by a diagnosis of the germinal factors. Fossil taxonomy is, in consequence, extremely arbitrary and unreliable. Many fossil forms classed as distinct species, or even as distinct genera, may be nothing more than fluctuants, mutants, hybrids, or immature stages of well-known species living today. Again, many fossils mistaken for distinct species are but different stages in the life-history of a single species, a mistake, which is unavoidable, when specimens are few and the age of the specimens unknown. The great confusion engendered in the classification of the hydrozoa by nineteenth-century ignorance of the alternation of hydroid and medusoid generations is a standing example of the danger of classifying forms without a complete knowledge of the entire life-cycle. When due allowance is made for mutation, hybridization, metagenesis, polymorphism, age and metamorphosis, the number of distinct fossil species will undergo considerable shrinkage. Nor must we overlook the possibility of environmentally-induced modifications. Many organisms, such as mollusks, undergo profound alteration as a result of some important, and, perhaps, relatively permanent, change in their environmental conditions, though such alterations affect only the phenotype, and do not involve a corresponding change in the specific genotype, i.e. the germinal constitution of the race.

In the degree that these considerations are taken into account the number of “extinct” fossil species will diminish and the number of “persistent” species will increase. This is a consummation devoutly to be wished for, but it means that hundreds of thousands of described species must needs be reviewed for the purpose of weeding out the duplicates, and who will have the knowledge, the courage, or even the span of life, necessary to accomplish so gigantic a task?

But so far as the practical purposes of our argument are concerned, the accepted list of persistent types needs no amplification. It suffices, as it stands, to establish the central fact (which, for the rest, is admitted by everyone) that some generic and even specific types have remained unchanged throughout the enormous lapse of time which has intervened between the deposition of the oldest strata and the advent of the present age. Our current theories, far from diminishing the significance of this fact, tend to intensify it by computing the duration of such persistence in millions, rather than in thousands, of years. Now, whatever one’s views may be on the subject of transformism, this prolonged permanence of certain genera and species is an indubitable fact, which is utterly irreconcilable with a universal law of organic evolution. The theory of transformism is impotent to explain an exception so palpable as this; for persistence and transmutation cannot be subsumed under one and the same principle. That which accounts for change cannot account for unchange. Yet unchange is an observed fact, while the change, in this case, is an inferred hypothesis. Hence, even if we accept the principle of transformism, there will always be scope for the principle of permanence. The extraordinary tenacity of type manifested by persistent genera and species is a phenomenon deserving of far more careful study and investigation than the evolutionally-minded scientist of today deigns to bestow upon it. To the latter it may seem of little consequence, but, to the genuine scientist, the actual persistence of types should be of no less interest than their possible variability.

With these reflections, our criticism of the palæontological argument terminates. The enumeration of its various deficiencies was not intended as a refutation. To disprove the theory of organic evolution is a feat beyond our power to accomplish. We can only adduce negative evidence, whose scope is to show that the various evolutionary arguments are inconsequential or inconclusive. We cannot rob the theory of its intrinsic possibility, and sheer justice compels us to confess that certain facts, like those of symbiotic preadaptation, lend themselves more readily to a transformistic, than to a fixistic, interpretation. On the other hand, nothing is gained by ignoring flaws so obvious and glaring as those which mar the cogency of palæontological “evidence.” The man who would gloss them over is no true friend either of Science or of the scientific theory of Evolution! They represent so many real problems to be frankly faced and fully solved, before the palæontological argument can become a genuine demonstration. But until such time as a demonstration of this sort is forthcoming, the evolutionist must not presume to cram his unsubstantiated theory down our reasonably reluctant throats. To accept as certain what remains unproved, is to compromise our intellectual sincerity. True certainty, which rests on the recognition of objective necessity, will never be attainable so long as difficulties that sap the very base of evolutionary argumentation are left unanswered; and, as for those who, in the teeth of discordant factual evidence, profess, nevertheless, to have certainty regarding the “fact” of evolution, we can only say that such persons cannot have a very high or exacting conception of what scientific certainty really means.

For the rest, it cannot even be said that the palæontological record furnishes good circumstantial evidence that our globe has been the scene of a process of organic evolution. In fact, so utterly at variance with this view is the total impression conveyed by the visible portion of the geological column, that the modern geologist proposes, as we have seen, to probe depths beneath its lowest strata for traces of that alleged transmutation, which higher horizons do not reveal. There are six to eight thick terranes below the Cambrian, we are told, and igneous masses that were formerly supposed to be basal have turned out to be intrusions into sedimentary accumulations, all of which, of course, is fortunate for the theory of organic evolution, as furnishing it with a sadly needed new court of appeal. The bottom, so to speak, has dropped out of the geological column, and Prof. T. C. Chamberlin announces the fact as follows: “The sharp division into two parts, a lifeless igneous base and a sedimentary fossiliferous superstructure, has given place to the general concept of continuity with merely minor oscillations in times and regions of major activity. Life has been traced much below the Cambrian, but its record is very imperfect. The recent discoveries of more ample and varied life in the lower Palæozoic, particularly the Cambrian, implies, under current evolutional philosophy, a very great downward extension of life. In the judgment of some biologists and geologists, this extension probably reaches below all the pre-Cambrian terranes as yet recognized, though this pre-Cambrian extension is great. The ‘Azoic’ bottom has retired to depths unknown. This profoundly changes the life aspect of the ‘column.’” (Science, Feb. 8, 1924, p. 128.) All this is doubtless true, but such an appeal, from the known to the unknown, from the actual to the possible, is not far-removed from a confession of scientific insolvency. Life must, of course, have had an earlier history than that recorded in the pre-Cambrian rocks. But even supposing that some portion of an earlier record should become accessible to us, it could not be expected to throw much light on the problem of organic origins. Most of the primordial sediments have long since been sapped and engulfed by fiery magmas, while terranes less deep have, in all probability, been so metamorphosed that every trace of their fossil contents has perished. The sub-Archæan beginnings of life will thus remain shrouded forever in a mystery, which we have no prospect of penetrating. Hence it is the exposed portion of the geological column which continues and will continue to be our sole source of information, and it is preëminently on this basis that the evolutionary issue will have to be decided.

Yet what could be more enigmatic than the rock record as it stands? For in nature it possesses none of that idealized integrity and coherence, with which geology has invested it for the purpose of making it understandable. Rather it is a mighty chaos of scattered and fragmentary fossiliferous formations, whose baffling complexity, discontinuity, and ambiguity tax the ingenuity of the most sagacious interpreters. Transformism is the key to one possible synthesis, which might serve to unify that intricate mass of facts, but it is idle to pretend that this theory is the unique and necessary corollary of the facts as we find them. The palæontological argument is simply a theoretical construction which presupposes evolution instead of proving it. Its classic pedigrees of the horse, the camel, and the elephant are only credible when we have assumed the “fact” of evolution, and even then, solely upon condition that they claim to approximate, rather than assign, the actual ancestry of the animals in question. In palæontology, as in the field of zoölogy, evolution is not a conclusion, but an interpretation. In palæontology, otherwise than in the field of genetics, evolution is not amenable to the check of experimental tests, because here it deals not with that which is, but with that which was. Here the sole objective basis is the mutilated and partially obliterated record of a march of events, which no one has observed and which will never be repeated. These obscure and fragmentary vestiges of a vanished past, by reason of their very incompleteness, lend themselves quite readily to all sorts of theories and all sorts of speculations. Of the “Stone Book of the Universe” we may say with truth that which Oliver Wendell Holmes says of the privately-interpreted Bible, namely, that its readers take from it the same views which they had previously brought to it. “I am, however, thoroughly persuaded,” say the late Yves Delage, “that one is or is not a transformist, not so much for reasons deduced from natural history, as for motives based on personal philosophic opinions. If there existed some other scientific hypothesis besides that of descent to explain the origin of species, many transformists would abandon their present opinion as not being sufficiently demonstrated.... If one takes his stand upon the exclusive ground of the facts, it must be acknowledged that the formation of one species from another species has not been demonstrated at all.” (“L’herédité et les grands problèmes de la biologie générale,” Paris, 1903, pp. 204, 322.)

II
THE PROBLEM OF ORIGINS

CHAPTER I
THE ORIGIN OF LIFE