297 FEW CHAPTER XII. EW of those who stand near some quarry in our inland counties, surrounded by all the beauties of British scenery, hill and valley, down and field, luxuriant with woods, carpeted with herbage, or waving with corn, bestow a thought on the character of the rock beneath. It occurs not to many, that where the grass now grows and the cattle low the waves once flowed; and that the ripple-mark may still be seen on what was once the ribbed sea sand. To those who are unacquainted with geology, it is startling to be told that the solid slab of stone so marked, when last exposed thousands of years ago, was part of the sandy shore over which the animated beings, now blotted from the book of life, wended their way, leaving in many cases the traces of their steps, just before some great convulsion of our planet changed the whole appearance of the surface, but spared these unmistakeable records to tell the tale. No one with any powers of generalization can long study the system of animated nature without being satisfied that he must search among the wrecks of bygone ages for those forms which are required to make it complete, and that in the fossil fauna he will find the lost links of the broken chain. Among the ichnolites, or fossil foot-prints, which have attracted so much attention of late years, those announced by Dr. Ogier Ward, as proving the existence of a small four-footed animal at the period of the deposition of the new red sandstone near Shrewsbury, were brought under the notice of the British Association at Birmingham. They most nearly resembled those figured in the paper on the new red sandstone of Warwickshire, by Sir Roderick Murchison and Mr. Strickland,* but differed in exhibiting more distinct indications of the terminal claws, and less distinctive impressions of the connecting web: the innermost toe was less, and there was an impression always at a distance from the fore-toes, like a hind-toe pointing backwards, the point of which only seemed to have touched the ground, reminding the observer of such an impression as might have been made by a wading bird, and of the 'ornithichnites' discovered by Dr. Hitchcock in the Connecticut new red sandstone, which have been referred to the grallatorial tribe of birds. The American fossil footsteps were found at five places near the banks of the river, within a distance of thirty miles, at various depths beneath the surrounding surface, in quarries of laminated flag-stones. The inclination of the stone is from 5° to 30°; and there is evidence to warrant the conclusion, that the tracks were impressed before the strata were so inclined. Many of these tracks, clearly showing that they belonged to different individuals and species, cross each other; and the footmarks are not unfrequently crowded together, reminding one of the impressions left by the feet of ducks, geese, and other birds, on the muddy shore of the stream or pond frequented by them. These foot-prints are referred by Professor Hitchcock to seven species at least, if not genera, of very long-legged wading birds, varying in size from that of a snipe to dimensions twice as great as those of an ostrich. The steps are seen in regular succession on a continuous track, as of an animal walking or running, the right and left foot always occupying their proper places. At Mount Thorn, near Northampton, were discovered four nearly parallel tracks of a gigantie animal, Geol. Trans. Second Series, vol. v. pl. xxviii. whose foot was fifteen inches long, exclusive of the largest claw, which was two inches in length. The toes were broad and thick, and in one track appeared a regular succession of six of these steps, four feet distant from each other. The distance in other tracks varied from four to six feet. Another footmark extended to the length of from fifteen to sixteen inches, without reckoning a remarkable appendage extending backwards eight or nine inches from the heel. The impressions of this appendage present traces similar to what may be made by wiry feathers or coarse bristles; these last appear to have sunk into the ground nearly an inch. The toes had penetrated much deeper, and the mud or sand appeared to have been raised into a ridge rising several inches around their impressions, reminding the observer of the elevation round the track of an elephant over moist clay. Intervals of six feet were noted as the length of the stride of the impressor of this so called ornithichnite. The bones of fishes only (Palæothrissum) had been discovered in this impressed rock. If Professor Hitchcock be right in his conclusion, that these enormous foot-prints are the vestiges of feathered giants, there can be no doubt that they justify the remark that they are of the highest interest to the palæontologist, as they establish the new fact of the existence of birds at the early epoch of the new red sandstone formation; and further show that some of the most ancient forms of that class attained a size far exceeding that of the largest among the feathered inhabitants of the present world. The discovery of the bones of the gigantic Dinornis (Owen), have proved beyond all question the last conclusion: but the student will do well, before he accepts the former, to investigate thoroughly Professor Owen's papers on Labyrinthodon,* remembering that the toes *Geol. Trans. Second Series. of Dr. Hitchcock's giant were broad and thick. The footmarks of that gigantic batrachian (Salamandroïdes, Jäger-Mastodonsaurus and Phytosaurus, of the same —Chirotherium, Kaup) were impressed on a shore; and in some of the specimens of that petrified strand were the impressions of drops of rain that had fallen upon the strata while in the process of formation. On the surface of one at Storeton, where the impressions of the footmarks were large, the depth of the holes made by the rain-drops on different parts of the same footstep varied with the unequal pressure on the clay and sand, according to the salient cushions and retiring hollows of the animal's foot. The constancy of these appearances upon an entire series of foot-prints in a long and continued track, showed that the rain had fallen after the creature had passed. The equable size of the casts of large drops that cover the entire surface of the slab (says Dr. Buckland, in his Address to the Geological Society of London on this phenomenon), except in the parts impressed by the cushions of the feet, records the falling of a shower of heavy drops on the day in which this huge animal had marched along the antient strand: hemispherical impressions of small drops upon another stratum, show it to have been exposed to only a sprinkling of gentle rain that fell at a moment of calm. In one small slab of new red sandstone, found by Dr. Ward near Shrewsbury [where the remains which will presently be alluded to were found], we have a combination of proofs as to meteoric, hydrostatic, and locomotive phenomena, which occurred at a time incalculably remote, in the atmosphere, the water, and the quarter towards which the animals were passing; the latter is indicated by the direction of the footsteps which form their tracks: the size and curvatures of the ripple-marks on the sand, now converted to sandstone, show the depth and direction of the current: the oblique impressions of the rain-drops register the point from which the wind was blowing at or about the time when the animals were passing. But how was this record so firmly imprinted on the stone? The answer is ready from the same eloquent and accurate oracle: The clay impressed with these prints of rain-drops acted as a mould, which transferred the form of every drop to the lower surface of the next bed of sand deposited upon it, so that entire surfaces of several strata in the same quarry are respectively covered with moulds and casts of drops of rain that fell whilst the strata were in process of formation.* No, you are not about to be dragged into a treatise on ichnology, friendly reader; though, believe me, you will find the subject, pregnant as it is with evidences of uncouth extinct forms that have passed away from life for ever, wending their way over the shores of a half-formed world, amid wind and rain, storm and sunshine, as marvellous, ay, and as entertaining too, as a fairy tale. You are only to be led to the contemplation of the ichnolites from the Shrewsbury sandstone, as a fit introduction to the crocodiles, which will next claim your attention. Professor Hitchcock, as we have seen, undoubtedly claims his ichnolites as due to the presence of birds on the spot where they were impressed; but, as Professor Owen well observes, any evidence of a warm-blooded and quick-breathing class of animals at so remote a period as the new red sandstone epoch, requires to be very closely sifted; and, accordingly, the chance of obtaining any analogical facts, bearing upon Professor Hitchcock's ornithichnites, induced our Professor to spare no exertions to obtain further insight into the problematical creature of the Grinsill quarries. Dr. Ward kept a sharp eye upon the quarrying operations; and soon, in addition to the footsteps, fossils were from time to time found, secured, and liberally sent up to the Professor, who was thus enabled to form a clear opinion of the animal that had impressed the sands with its feet. The result was the Professor's Description of an Extinct Lacertian Reptile, Rhynchosaurus articeps * Address delivered to the Geological Society of London on the 21st February, 1840, by the Rev. W. Buckland, D.D. President. |