some fine remains of the Eningen Salamander in the collection of the British Museum. LIGN. 138.-FOSSIL SALAMANDER OF CENINGEN: CRYPTOBRANCHUS SCHEUCHZERI. ("Homo Diluvii Testis" of Scheuchzer. Four and a half feet in length.) 31. REVIEW OF THE AGE OF REPTILES.-From the examination of the organic remains of the Secondary Formations we obtain the following results: that the seas, lakes, and rivers during these geological periods swarmed with reptiles, fishes, mollusca, crustacea, annelida, echinodermata, zoophytes, foraminifera, sponges, and sea-weeds; all of extinct species, and presenting, as a whole, a greater discrepancy with existing forms than those of the Tertiary; the most remarkable feature being the apparent absence of Cetacea (p. 325), and the presence of several genera of marine Reptiles. On the land we find but little analogy to the terrestrial inhabitants belonging to the tertiary or present eras: throughout the vast accumulations of the spoils of the ancient Islands and Continents, although the remains of crocodiles, fresh-water turtles, insects, and terrestrial plants abound, a few jaws of very small animals are the sole indications of the existence of Mammalia; and the evidence of the presence of Birds is even less clear. In vain we seek for the relics of Man, or the remains of works of art,-for the skeletons of the Mastodon or the Mammoth,-of the Palæotheres, or other mammals that were their contemporaries; the osseous remains of terrestrial and fluviatile Reptiles alone appear. In the emphatic language of Cuvier, “Nous remontons donc à un autre âge du monde,—à cet âge où la terre n'étoit encore parcourue que par des reptiles à sang froid, où la mer abondoit en ammonites, en bélemnites, en térébratules, en encrinites, et où tous ces genres, aujourd'hui d'une rareté prodigieuse, faisoient le fond de sa population."* The earliest indications of air-breathing vertebrate animals is the little Elgin reptile, and the supposed imprints of chelonian footsteps in Devonian sandstone. In the succeeding Carboniferous, Permian, and Triassic periods, Saurobatrachians occur, often of great bulk, and in great numbers; and on the later sands of those old shores are found the foottracks of bipeds which seem to point to a higher class, that of birds, for their origin. In the following periods, embracing the deposition of the Lias, Oolite, Wealden, and Chalk, swarms of reptiles belonging to numerous genera everywhere prevail; species fitted to live in the air, on the land, in lakes and rivers, and in the seas,-yet not one identical with any existing form. These gradually decline as we approach the close of the secondary, and are succeeded in the tertiary by as varied modifications of the higher animals-the mammalia and birds. Thus, the faunas of the vast periods that intervened between the tertiary and palæozoic ages present the following numerical relations in the three higher classes of the vertebrata : Seven † genera of small land-animals (p. 394, 508, and 561). Wirtemberg, Stonesfield, and Purbeck. "Ossemens Fossiles," tome v. 2de partie, p. 10. Mr. Beckles has specimens of other Purbeck genera, still undescribed. The Dromatherium (Emmons), being probably Permian, is not reckoned here. BIRDS REPTILES . A species from North Carolina (p. 558, note); another from Stonesfield? (p. 524); another from the Wealden? (p. 452); and many species inferred from footprints on sandstone of the Triassic period? (p. 557). Marine;—Fifty genera, including above one hundred and forty species. - Terrestrial and Fluviatile; - Forty-five genera, comprising about two hundred species. Flying;-Two genera, containing nineteen species. Here, then, the classes Mammalia and Aves, which constitute the essential features of the existing terrestrial faunas of almost all countries, are represented through a period of time of incalculable duration, by a few diminutive quadrupeds, by some uncertain vestiges of birds, and problematical foot-prints of bipeds on the rocks; while everywhere bones, teeth, and entire skeletons of reptilian forms, adapted for aerial, terrestrial, and aquatic existence, afford unequivocal proofs that the air, the land, and the waters were tenanted by cold-blooded vertebrate animals. In the succeeding tertiary ages, the fossil remains of reptiles belong to species of existing types, and are associated with the relics of innumerable mammiferous quadrupeds. Now, if we admit, to the utmost extent, the effect of causes that may be supposed to have operated to the exclusion of the remains of mammalia from the secondary formations, still the overwhelming preponderance of the reptilian tribes, both on the land and in the waters, is most striking. And here we may inquire whether this remarkable phenomenon warrants the hypothesis which some eminent geologists have advanced, namely, that during the periods antecedent to the eocene, the earth was not adapted for the existence of mammalia ?-that it was in a state of turbulence and convulsion, which colossal reptile forms were alone calculated to endure; that it was a half-finished planet, unsuitable for warm-blooded animals; and that its atmosphere was incapable of supporting the higher types of animal organization? The probability that birds existed in the country of the Iguanodon-the certainty that marsupial and insectivorous mammals were the contemporaries of the Megalosaurus and Pterodactyles--that trees and plants, similar to many which now grow in regions abounding in birds and warmblooded quadrupeds, flourished throughout the "Age of Reptiles," are facts which appear to me fatal to such a hypothesis, and to prove that the general temperature of the earth, and the physical constitution of the sea, and the atmosphere, were not essentially different from those which now prevail. That the class of reptiles was developed, throughout the periods embraced in this review, to an extent far beyond what has since taken place, cannot, I conceive, by any legitimate process of reasoning be disputed; but I do not think that in the present state of our knowledge any satisfactory explanation of this extraordinary fact can be offered. 32. OBJECTIONS CONSIDERED.-There are persons who, with one of the Bridgewater essayists (Mr. Kirby *), oppose these conclusions, and have recourse to the most strange conceits to account for the phenomena on which they are founded. But it is for those who refuse their assent to deductions made with the greatest caution, and derived from an overwhelming mass of evidence, to explain the entire absence of all traces, not only of Man, but of the whole existing species of animals and vegetables, in the ancient deposits; while there is not a river or stream which does not daily imbed the remains of the present inhabitants of the globe. But, however future discoveries may modify this hypothesis, they cannot invalidate the fact, that there is no country on the face of the earth with such an assemblage of animal life as that possessed by the regions whence the delta of the Wealden was derived; nowhere is there an island or a con * Seventh Bridgewater Treatise. tinent inhabited by colossal reptiles only, or (excepting the Galapagos) where the Reptilia usurp the place of the large Mammalia. We have seen that this feature in the zoology of that remote period was not confined to the country of the Iguanodon; in every part of the world where geological researches have extended, this wonderful phenomenon appears -the absence of mammiferous animals in the older strata. The bones of reptiles, sometimes of enormous size, are there the only remains of the higher animals (except fishes) that occur in any considerable number. It is, therefore, manifest, that there was a period when oviparous quadrupeds of appalling magnitude were the chief possessors of the lands of which any traces remain in the strata that are accessible to human observation. I do not, however, mean to aver, that reptiles, and reptiles only, were the occupiers of every Island and Continent; but that it appears from the most irrefragable testimony, that the reptile tribes during the secondary periods were developed to an extent of which the present state of animated nature affords no example. It must be acknowledged that the proposition is astounding, and I do not feel any surprise that many intelligent persons, whose attention has not previously been directed to geological inquiries, should hesitate to admit its correctness; but the conclusion is drawn from such an immense accumulation of facts, corroborated by observations made in every region of the earth, as to compel assent, in spite of all our preconceived opinions. We may, indeed, call up from the depths of our ignorance hypotheses as marvellous as the phenomena they are intended to explain, but which a very slight examination of the facts before us would prove to be untenable. 33. CONCLUDING REMARKS.-There is another objection to which I would allude; for I do not think with some, that the errors or prejudices of those who differ from us should be treated with silence or contempt; but, rather, that it is |