[712] With regard to the distribution of reptilian life during the carboniferous and succeeding epochs, see above, page 748.
The sandstones of the New Red or Triassic series frequently retain the track-prints of animals, and numerous notices of such occurrences have been published.[713] In addition to the account of these invaluable evidences of the existence of bygone creatures that is here given, the attention of students is especially directed to Dr. Buckland’s most interesting description and illustrations of such as were known when his Treatise was published (Bd. i. p. 259, &c.; and ii. p. 36, pl. xxvi. &c.).
[713] The following are the principal notices of ichnolites by English authors which are not referred to in the text:—Cunningham, Yates, and Egerton on Cheirotherian traces in Cheshire, Geol. Proc. vol. iii. pp. 12-15; Dr. Black on foot-prints at Runcorn, Quart. Geol. Journ. vol. ii. p. 65, pl. ii.; Mr. Cunningham. Liverpool Lit. and Phil. Proc. 1848, p. 129, plates iii.-v.; Mr. Hawkshaw on the New Red with foot-prints at Lymm, Rep. Brit. Assoc. 1842, Sect. p. 56; Mr. Rawlinson on the same, Quart. Geol. Journ. vol. ix. p. 37; Prof. Harkness on the track-bearing beds of Dumfriesshire, Rep. Brit. Assoc. 1850, Sect. p. 83; Quart. Geol. Journ. vol. vi. pp. 389 and 393; and Annals Nat. Hist. 1850, vol. vi. p. 203; Sir W. Jardine, Annals Nat. Hist. loc. cit. Foreign authorities may be found by reference to Pictet’s Traité de Paléontologie, a new and enlarged edition, vol. i. 1853, p. 567, et seq.
The imprints of the feet of some large quadrupeds, having the fore-paws much smaller than the hinder, have been found in Saxony (see Wond. p. 555, Bd. p. xxvi.); and also in strata of the same age in Warwickshire and Cheshire. The quarries at Storeton Hill, near Liverpool, are celebrated for the abundance and variety of these imprints.[714] Some of the strata of sandstone in this locality are divided by thin beds of clay; a lithological structure which admits of the ready separation of the stone in the direction of the sedimentary planes.
[714] The Museums at Warwick, Warrington, and Liverpool are rich in impressed slabs from the Triassic districts. Numerous fine specimens may be also seen in the Museum of the Geological Society, Somerset House, the Museum of Practical Geology, in Jermyn Street, and in the British Museum (see Petrif. pp. 14 and 63).
RAIN-PRINTS ON STONE.
Imprints are found on the face of each successive stratum; and on some of the layers, not only the tracks of animals that have walked over the clay when soft are distinctly observable, but the surface is often traversed with casts of the cracks caused by the desiccation of one layer of clay previously to the deposition of the succeeding layer of sand or mud; and it often presents a blistered or warty appearance, being covered with either little hemispherical eminences or depressions, which an accurate investigation of the phenomenon has proved to have been produced by showers of rain (Ly. figs. 526-528). On the slabs of sandstone, the forms of the sun-cracks, rain-drops, and foot-prints appear in relief, being casts moulded in the soft clayey mud upon which the original impressions were made; while on the clay or shale, corresponding depressions are apparent.[715]
[715] The impressions of rain-drops on stone were first noticed, and their origin explained, by Mr. Cunningham. Geol. Proc. vol. iii. p. 99. See also an interesting Paper by Sir C. Lyell, Quart. Geol. Journ. vol. vii. p. 240.
The foot-prints on these strata are of several kinds; some appear to have been produced by small reptiles and crustaceans; but the principal imprints are identical with those which have been observed in Saxony, and are referable to some large quadruped, in which the fore-feet were of a much smaller size than the hind-feet ([Lign. 245]). From a supposed resemblance of the imprints to those of a human hand, Professor Kaup proposed the name of Cheirotherium, to designate the unknown animal which had left these "footsteps on the sands of Time." But since Professor Owen’s discovery, that the bones and teeth of reptiles found in similar strata in Warwickshire belong to gigantic Batrachians, and since the fore and hind-feet of the frog-tribe are often as dissimilar in size as the impressions of the Cheirotherium, it has been suggested, with much probability, that the foot-prints in question may be those of Labyrinthodonts; but until the form of the feet of these extinct Batrachians can be ascertained, this inference must be regarded as conjectural (Ly. fig. 331).
CHEIROTHERIUM.