The Foot-prints of the Creator

by Hugh Miller

In the marine and lacustrine floras of the lake, Mr. Miller observed changes still more palpable. At the entrance of the sea, the Fucus nodosus and Fucus vesiculosus flourish in their proper form and magnitude. A little farther on in the lake, the F. nodosus disappears, and the F. vesiculosus, though continuing to exist for mile after mile, grows dwarfish and stunted, and finally disappears, giving place to rushes and other aquatic grasses, till the lacustrine has entirely displaced the marine flora. From these two important facts, the existence of the fragment of Asterolepis in the lower flagstones of the Orkneys, and of the “curiously mixed semi-marine semi-lacustrine vegetation in the Loch of Stennis,” which our author regards as bearing directly on the development hypothesis, he takes occasion to submit that hypothesis to a severe examination, and to point out its consequences—its incompatibility with the great truths of morality and revealed religion. According to Professor Oken, one of the ablest supporters of the development theory, “There are two kinds of generation in the world, the creation proper, and the propagation that is sequent thereon, or the original and secondary generation. Consequently, no organism has been created of larger size than an infusorial point. No organism is, or ever has been created, which is not microscopic. Whatever is large has not been created, but developed. Man has not been created, but developed.” Hence it follows that during the great geological period, when race after race was destroyed, and new forms of life called into being, “nature had been pregnant with the human race,” and that immortal and intellectual Man is but the development of the Brute—itself the development of some monad or mollusc, which has been smitten into life by the action of electricity upon a portion of gelatinous matter.

If the development theory be true, “the early fossils ought to be very small in size,” and “very low in organization.” In the earliest strata we ought to find only “mere embryos and fœtuses; and if we find instead the full-grown and mature, then must we hold that the testimony of geology is not only not in accordance with the theory, but in positive opposition to it.” Having laid this down as the principle by which the question is to be decided, our author proceeds to consider “what are the facts.” The Asterolepis of Stromness seems to be the oldest organism yet discovered in the most ancient geological system of Scotland, in which vertebrate remains occur. It is probably the oldest Cœlacanth that the world has yet produced, for there is no certain trace of this family in the great Silurian system, which lies underneath, and on which, according to our existing knowledge, organic existence first began. “How, then,” asks Mr. Miller, “on the two relevant points—bulk and organization—does it answer to the demands of the development hypothesis? Was it a mere fœtus of the finny tribe, of minute size and imperfect embryonic faculty? Or was it of, at least, the ordinary bulk, and, for its class, of the average organization?”

In order to answer these questions, Mr. Miller proceeds in his third chapter to give the recent history of the Asterolepis; in his fourth, to ascertain the cerebral development of the earlier vertebrata; and in his fifth chapter to describe the structure, bulk, and aspect of the Asterolepis. In the rocks of Russia certain fossil remains had been long ago discovered, of such a singular nature as to have perplexed Lamarck and other naturalists. Their true place among fishes was subsequently ascertained by M. Eichwald, a living naturalist; and Sir Roderick Murchison found that they were Ichthyolites of the Old Red Sandstone. Agassiz gave them the name of Chelonichthys; but in consequence of very fine specimens having been found in the Old Red Sandstone of Russia, which Professor Asmus of Dorpat sent to the British Museum, and which exhibited star-like markings, he abandoned his name of Chelonichthys, and adopted that of Asterolepis, or star-scale, which Eichwald had proposed. Many points, however, respecting this curious fossil remained to be determined, and it was fortunate for science that Mr. Miller was enabled to accomplish this object by means of a variety of excellent specimens which he received from Mr. Robert Dick, “an intelligent tradesman of Thurso, one of those working men of Scotland, of active curiosity and well developed intellect, that give character and standing to the rest.” Agassiz had inferred, from very imperfect fragments, that the Asterolepis was a strongly-helmed fish of the Cœlacanths, or hollow spine family—that it was probably a flat-headed animal, and that the discovery of a head or of a jaw might prove that the genus Dendrodus did not differ from it. All these conjectures were completely confirmed by Mr. Miller, after a careful examination of the specimens of Mr. Dick.

Before proceeding to describe the structure of the gigantic Asterolepis, Mr. Miller devotes a long and elaborate chapter to the subject of the cerebral development of the earlier vertebrata, in order to ascertain in what manner their true brains were lodged, and to discover the modification which the cranium, as their protecting box, received in subsequent periods. This inquiry, which he has conducted with great skill and ability, is not only highly interesting in itself, but will be found to have a direct bearing on the great question which it is his object to discuss and decide.

The facts and reasonings contained in this chapter will, we doubt not, shake to its very base the bold theory of Professor Oken, which has been so generally received abroad, and which is beginning to find supporters even among the solid thinkers of our own country. In the Isis of 1818, Professor Lorenz Oken has given the following account of the hypothesis to which we allude. “In August, 1806,” says he, “I made a journey over the Hartz. I slid down through the wood on the south side, and straight before me, at my very feet, lay a most beautiful blanched skull of a hind. I picked it up, turned it round, regarded it intensely;—the thing was done. ‘It is a vertebral column,’ struck me like a flood of lightning, ‘to the marrow and bone;’ and since that time the skull has been regarded as a vertebral column.”

This remarkable hypothesis was at first received with enthusiasm by the naturalists of Germany, and, among others, by Agassiz, who, from grounds not of a geological kind, has more recently rejected it. It has been adopted by our distinguished countryman, Professor Owen, and forms the central idea in his lately published and ingenious work “On the Nature of Limbs.” The conclusion at which he arrives, that the fore-limbs of the vertebrata are the ribs of the occipital bone or vertebra set free, and (in all the vertebrata higher in the scale than the ordinary fishes) carried down along the vertebral column by a sort of natural dislocation, is a deduction from the idea that startled Professor Oken in the forest of the Hartz. Whatever support this hypothesis might have expected from Geology, has been struck from beneath it by this remarkable chapter of Mr. Miller’s work; and though anatomists may for a while maintain it under the influence of so high an authority as Professor Owen, we are much mistaken if it ever forms a part of the creed of the geologist. Mr. Miller indeed has, by a most skilful examination of the heads of the earliest vertebrata known to geologists, proved that the hypothesis derives no support from the structure which they exhibit, and Agassiz has even upon general principles rejected it as untenable.

Mr. Miller’s next chapter on the structure, bulk, and aspect of the Asterolepis, is, like that which precedes it, the work of a master, evincing the highest powers of observation and analysis. Its size in the larger specimens must have been very great; and from a comparison of the proportion of the head in the Ganoids to the length of the body, which is sometimes as one to five, or one to six, or one to six and a half, or even one to seven, our author concludes that the total length of the specimens in his possession must have been at least eight feet three inches, or from nine feet nine to nine feet ten inches. The remains of an Asterolepis found by Mr. Dick at Thurso, indicate a length of from twelve feet five to thirteen feet eight inches; and one of the Russian specimens of Professor Asmus must have been from eighteen to twenty-three feet long. “Hence,” says Mr. Miller, “in the not unimportant circumstance of size—the most ancient Cœlacanths yet known, instead of taking their places agreeably to the demands of the development hypothesis among the sprats, sticklebacks, and minnows of their class, took their place among its huge basking sharks, gigantic sturgeons, and bulky swordfishes. They were giants, not dwarfs.” Again, judging by the analogies which its structure exhibits to that of fishes of the existing period, the Asterolepis must have been a fish high in the scale of organization.

A specimen of Asterolepis, discovered by Mr. Dick, among the Thurso rocks, and sent to Mr. Miller, exhibited the singular phenomenon of a quantity of thick tar lying beneath it, which stuck to the fingers when lifting the pieces of rock. “What had been once the nerves, muscles, and blood of this ancient Ganoid, still lay under its bones,” a phenomenon which our author had previously seen beneath the body of a poor suicide, whose grave in a sandy bank had been laid open by the encroachments of a river, the sand beneath it having been “consolidated into a dark colored pitchy mass,” extending a full yard beneath the body. In like manner, the animal juices of the Asterolepis had preserved its remains, by “the pervading bitumen, greatly more conservative in its effects than the oil and gum of an old Egyptian undertaker.” The bones, though black as pitch retained to a considerable degree the peculiar qualities of the original substance, in the same manner as the adipocire of wet burying-grounds preserves fresh and green the bones which it encloses.

In support of his anti-development views, Mr. Miller devotes his next and sixth chapter to the recent history, order, and size of the fishes of the Upper and Lower Silurian rocks. Of these ancient formations, the bone bed of the Upper Ludlow rocks is the only one which, besides defensive spines of fish, contains teeth, fragments of jaws, and shagreen points, whereas, in the inferior deposits, defensive spates alone are found. The species discovered by Professor Phillips, in the Wenlock shale, were microscopic; and the author of the Vestiges took advantage of this insulated fact to support his views, by pronouncing the little creatures to which the species belonged as the fœtal embryos of their class. Mr. Miller has, however, even on this ground, defeated his opponent. By comparing the defensive spines of the Onchus Murchisoni of the Upper Ludlow bed with those of a recent Spinax Acanthias, or dog-fish, and of the Cestracion Phillippi, or Port Jackson shark, he arrives at the conclusion, that the fishes to which the species belonged must be all of considerable size; and in the following chapter on the high standing of the Placoids he shews that the same early fishes were high in intelligence and organization.