The Old Red Sandstone; or, New Walks in an Old Field

by Hugh Miller

[AS] May I crave the attention of the reader to a brief statement of fact? I have said that Professor Fleming, when he minutely described the scales of the Holoptychius, hazarded no conjecture regarding the generic character of the creature to which they had belonged; he merely introduced them to the notice of the public as the scales of some "vertebrated animal, probably those of a fish." I now state that he described the scales of a contemporary ichthyolite as bearing, in external appearance, a "close resemblance to some of the scales of the common sturgeon." It has been asserted, that it was the scales of the Holoptychius which he thus described, "referring them to an extinct species of the genus Accipenser;" and the assertion has been extensively credited, and by some of our highest geological authorities. Agassiz himself, evidently in the belief that the professor had fallen into a palpable error, deems it necessary to prove that the Holoptychius could have borne "no relation to the Accipenser or sturgeon." Mr. Murchison, in his Silurian System, refers also to the supposed mistake. The person with whom the misunderstanding seems to have originated is the Rev. Dr. Anderson, of Newburgh. About a twelvemonth after the discovery of Professor Fleming in the sandstones of Drumdryan, a similar discovery was made in the sandstones of Clashbennie by a geologist of Perth, who, on submitting his new found scales to Dr. Anderson, concluded, with the Doctor, that they could be no other than oyster shells; though eventually, on becoming acquainted with the decision of Professor Fleming regarding them, both gentlemen were content to alter their opinion, and to regard them as scales. The Professor, in his paper on the Old Red Sandstone in Cheek's Journal, referred incidentally to the oyster shells of Clashbennie—a somewhat delicate subject of allusion; and in Dr. Anderson's paper on the same formation, which appeared about seven years after, in the New Journal of Professor Jameson, the geological world was told, for the first time, that Professor Fleming had described a scale of Clashbennie similar to those of Drumdryan, (i. e., those of the Holoptychius,) as bearing a "close resemblance to some of the scales on the common sturgeon," and as probably referable to some "extinct species of the genus Accipenser." Now, Professor Fleming, instead of stating that the scales were at all similar, had stated very pointedly that they were entirely different; and not only had he described them as different, but he had also figured them as different, and had placed the figures side by side, that the difference might be the better seen. To the paper of the Professor, which contained this statement, and to which these figures were attached, Dr. Anderson referred, as "read before the Wernerian Society;"—he quoted from it in the Professor's words—he drew some of the more important facts of his own paper from it—in his late Essay on the Geology of Fife he has availed himself of it still more largely, though with no acknowledgment; it has constituted, in short, by far the most valuable of all his discoveries in connection with the Old Red Sandstone, and apparently the most minutely examined; and yet, so completely did he fail to detect Professor Fleming's carefully drawn distinction between the scales of the Holoptychius and those of its contemporary, that when Agassiz, misled apparently by the Doctor's own statement, had set himself to show that the scaly giant of the formation could have been no sturgeon, the Doctor had the passage in which the naturalist established the fact transferred into a Fife newspaper, with, of course, the laudable intention of preventing the Fife public from falling into the absurd mistake of Professor Fleming. There seems to be something rather inexplicable in all this; but there can be little doubt Dr. Anderson could satisfactorily explain the whole matter without once referring to the oyster shells of Clashbennie. It is improbable that he could have wished or intended to injure the reputation of a gentleman to whose freely-imparted instructions he is indebted for much the greater portion of his geological skill—whose remarks, written and spoken, he has so extensively appropriated in his several papers and essays—and whose character is known far beyond the limits of his country, for untiring research, philosophic discrimination, and all the qualities which constitute a naturalist of the highest order. Dr. Johnston, of Berwick, in his History of British Zoöphytes, (a work of an eminently scientific character,) justly "ascribes to the labors and writings" of Professor Fleming "no small share in diffusing that taste for Natural History which is now abroad." And as an interesting corroboration of the fact, I may state, that Dr. Malcolmson, of Madras, lately found an elegant Italian translation of Fleming's Philosophy of Zoölogy, high in repute among the elite of Rome. Lest it should be supposed I do Dr. Anderson injustice in these remarks, I subjoin the grounds of them in the following extracts from professor Fleming's paper in Cheek's Journal, and from the paper in Jameson's New Edinburgh Journal, in which the Doctor purports to give a digest of the former, without once referring, however, to the periodical in which it is to be found:—

"In the summer of 1827," says Dr. Fleming, "I obtained from Drumdryan quarry, to the south of Cupar, situate in the higher strata of yellow sandstone, certain organisms, which I readily referred to the scales of vertebrated animals, probably those of a fish. The largest (see [Plate II.], fig. 1, 'figure of a scale of the Holoptychius') was one inch and one tenth in length, about one inch and two tenths in breadth, and not exceeding the fiftieth of an inch in thickness. The part which, when in its natural position, had been imbedded in the cuticle, is comparatively smooth, exhibiting, however, in a very distinct manner, the semicircularly parallel layers of growth with obsolete diverging striæ, giving to the surface, when under a lens, a reticulated aspect. The part naturally exposed is marked with longitudinal, waved, rounded, anastomosing ridges, which are smooth and glossy. The whole of the inside of the scale is smooth, though exhibiting with tolerable distinctness the layers of growth. The form and structure of the object indicated plainly enough that it had been a scale, a conclusion confirmed by the detection of the phosphate of lime in its composition. At this period I inserted a short notice of the occurrence of these scales in our provincial newspaper, the Fife Herald, for the purpose of attracting the attention of the workmen and others in the neighborhood, in order to secure the preservation of any other specimens which might occur.

"Nearly a year after these scales had been discovered, not only in the upper, but even in some of the lower beds of the Yellow Sandstone, I was informed that oyster shells had been found in a quarry in the Old Red Sandstone at Clashbennie, near Errol, in Perthshire, and that specimens were in the possession of a gentleman in Perth. Interested in the intelligence, I lost no time in visiting Perth, and was gratified to find that the supposed oyster shells were, in fact, similar to those which I had ascertained to occur in a higher part of the series. The scales were, however, of a larger size, some of them exceeding three inches in length, and one eighth of an inch in thickness. Upon my visit to the quarry, I found the scales, as in the Yellow Sandstone, most abundant in those parts of the rock which exhibited a brecciated aspect. Many patches a foot in length, full of scales, have occurred; but as yet no entire impression of a fish has been obtained.

"Another scale, differing from those already noticed, (see [Plate II.], fig. 3, 'figure of an oblong tubercle plate traversed diagonally by lines, which, bisecting one another a little above the centre, resembles a St. Andrew's cross, and marked on the edges by faintly radiating lines,') is about an inch and a quarter in length, and an inch in breadth. In external appearance it bears a very close resemblance to some of the scales on the common sturgeon, and may, with some probability, be referred to an extinct species of the genus Accipenser."—(Cheek's Edinburgh Journal, Feb. 1831, p. 85.)

"Dr. Fleming, in 1830," says Dr. Anderson, "read before the Wernerian Society a notice 'on the occurrence of scales of vertebrated animals in the Old Red Sandstone of Fifeshire.' These organisms, as described by him, occurred in the Yellow Sandstone of Drumdryan and the Gray Sandstone of Parkhill. From the former locality scales of a fish were obtained.... The same paper (Professor Fleming's) contains a notice of similar scales in the Old Red Sandstone of Clashbennie, near Errol, in Perthshire, one of which is described as bearing 'a very close resemblance to some of the scales on the common sturgeon, and may with some probability be referred to an extinct species of the genus Accipenser.'"—(Professor Jameson's Edin. New Phil. Journal, Oct. 1837, p. 138.)

The deposit, too, abounds in teeth, various enough in their forms to indicate a corresponding variety of families and genera among the ichthyolites to which they belonged. Some are nearly straight, like those of the Holoptychius of the Coal Measures; some are bent, like the beak of a hawk or eagle, into a hook-form; some incline first in one direction, and then in the opposite one, like nails that have been drawn out of a board by the carpenter at two several wrenches, and bent in opposite angles at each wrench; some are bulky and squat, some long and slender; and in almost all the varieties, whether curved or straight, squat or slim, the base is elegantly striated like the flutings of the column. In the splendid specimen found in the sandstones of the Findhorn, the tooth is still attached to a portion of the jaw, and shows, from the nature of the attachment, that the creature to which it belonged must have been a true fish, not a reptile. The same peculiarity is observable in two other very fine specimens in the collection of Mr. Patrick Duff, of Elgin. Both in saurians and in toothed cetaceæ, such as the porpoise, the teeth are inserted in sockets. In the ichthyolites of this formation, so far as these are illustrated by its better specimens, the teeth, as in existing fish, are merely placed flat upon the jaw, or in shallow pits, which seem almost to indicate that the contrivance of sockets might be afterwards resorted to. Immediately over the sandstone and conglomerate belt in which these organisms occur, there rests, as has been said, a band of limestone, and over the limestone a thick bed of yellow sandstone, in which the system terminates, and which is overlaid in turn by the lower beds of the carboniferous group.

The limestone band is unfossiliferous, and resembling, in mineralogical character, the Cornstones of England and Wales, it has been described as the Cornstone of Scotland; but the fact merely furnishes one illustration of many, of the inadequacy of a mineralogical nomenclature for the purposes of the geologist. In the neighborhood of Cromarty the lower formation abounds in beds of nodular limestone, identical in appearance with the Cornstone;—in England similar beds occur so abundantly in the middle formation, that it derives its name from them;—in Fife they occur in the upper formation exclusively. Thus the formation of the Coccosteus and Dipterus is a cornstone formation in the first locality; that of the Cephalaspis and the gigantic lobster in the second; that of the Holoptychius nobilissimus in the third. We have but to vary our field of observation to find all the formations of the system Cornstone formations in turn. The limestone band of the upper member presents exactly similar appearances in Moray as in Fife. It is in both of a yellowish green or gray color, and a concretionary structure, consisting of softer and harder portions, that yield so unequally to the weather, as to exhibit in exposed cliffs and boulders a brecciated aspect, as if it had been a mechanical, not a chemical deposit; though its origin must unquestionably have been chemical. It contains minute crystals of galena, and abounds in masses of a cherty, siliceous substance that strikes fire with steel, and which, from the manner in which they are incorporated with the rock, show that they must have been formed along with it. From this circumstance, and from the general resemblance it bears to the deposits of the thermal waters of volcanic districts which precipitate siliceous mixed with calcareous matter, it has been suggested, and by no mean authority, that it must have derived its origin from hot springs. The bed is several yards in thickness; and as it appears both in Moray and in Fife, in localities at least a hundred and twenty miles apart, it must have been formed, if formed at all, in this manner, at a period when the volcanic agencies were in a state of activity at no great distance from the surface.

The upper belt of yellow stone, the terminal layer of the pyramid, is fossiliferous both in Moray and Fife—more richly so in the latter county than even the conglomerate belt that underlies it, and its organisms are better preserved. It was in this upper layer, in Drumdryan quarry, to the south of Cupar, that Professor Fleming found the first-discovered scales of the Holoptychius. At Dura Den, in the same neighborhood, a singularly rich deposit of animal remains was laid open a few years ago, by some workmen, when employed in excavating a water-course for a mill. The organisms lay crowded together, a single slab containing no fewer than thirty specimens, and all in a singularly perfect state of preservation. The whole space excavated did not exceed forty square yards in extent, and yet in these forty yards there were found several genera of fishes new to Geology, and not yet figured nor described—a conclusive proof in itself that we have still very much to learn regarding the fossils of the Old Red Sandstone. By much the greater portion of the remains disinterred on this occasion were preserved by a lady in the neighborhood; and the news of the discovery spreading over the district, the Rev. Dr. Anderson, of Newburgh, was fortunately led to discover them anew in her possession. The most abundant organism of the group was a variety of Pterichthys—the sixth species of this very curious genus now discovered in the Old Red Sandstones of Scotland; and as the Doctor had been lucky enough to find out for himself, some years before, that the scales of the Holoptychius were oyster shells, he now ascertained, with quite as little assistance from without, that the Pterichthys must have been surely a huge beetle. As a beetle, therefore, he figured and described it in the pages of a Glasgow topographical publication—Fife Illustrated. True, the characteristic elytra were wanting, and some six or seven tubercle plates substituted in their room; nor could the artist, with all his skill, supply the creature with more than two legs; but ingenuity did much for it, notwithstanding; and by lengthening the snout, insect-like, into a point—by projecting an eye, insect-like, on what had mysteriously grown into a head—by rounding the body, insect-like, until it exactly resembled that of the large "twilight shard"—by exaggerating the tubercles seen in profile on the paddles until they stretched out, insect-like, into bristles—and by carefully sinking the tail, which was not insect-like, and for which no possible use could be discovered at the time—the Doctor succeeded in making the Pterichthys of Dura Den a very respectable beetle indeed. In a later publication, an Essay on the Geology of Fifeshire, which appeared in September last in the Quarterly Journal of Agriculture, he states, after referring to his former description, that among the higher geological authorities some were disposed to regard the creature as an extinct crustaceous animal, and some as belonging to a tribe closely allied to the Chelonia. Agassiz, as the writer of these chapters ventured some months ago to predict, has since pronounced it a fish—a Pterichthys specifically different from the five varieties of this ichthyolite which occur in the lower formation of the system, but generically the same. I very lately enjoyed the pleasure of examining the bona fide ichthyolite itself—one of the specimens of Dura Den, and apparently one of the more entire—in the collection of Professor Fleming. Its character as a Pterichthys I found very obvious; but neither the Professor nor myself was ingenious enough to discover in it any trace of the beetle of Dr. Anderson.[AT]

[AT] This interesting ichthyolite has since been regarded by Agassiz as the representative of a distinct genus, to which he gives the name Pamphractus. As exhibited in his restoration, however, it seems to differ little, if at all, (if I may venture the suggestion,) from a Pterichthys viewed on the upper side. In Agassiz's beautiful restoration of Pterichthys, and his accompanying prints of the fossils illustrative of that genus, it is, with but one doubtful exception, the under side of the animal that is presented; and hence a striking difference apparent between his representations of the two genera, which would scarce obtain had the upper, not the under side of Pterichthys been exhibited. In verification of this remark, let the reader who has access to the Monographic Poissons Fossiles compare the restoration of Pamphractus (Old Red, Tab. VI., fig. 2) with the upper side of Pterichthys, as figured in this volume, [Plate I.], fig. 1, making, of course, the due allowance for a difference of species.