138 Proceedings of the British Association* 



animals — the lias, with its no less wonderful saurians and shells, — not 

 the shells of the present seas — not the crocodile of the Nile or the 

 Ganges, but forms now utterly past away, we must pause for a 

 minute to consider the startling announcement made by the Dean re- 

 specting this period. He says, that after the trilobites and crinoidea 

 had been buried by the mighty inundation he had brought over the 

 earth, and after the saurians and other inhabitants of the shore were 

 intombed, we should expect to find next those " heavy animals who 

 were unable to fly fast enough to the hills, the megatheria, didelphys 

 pterodactyle, &c." In this selection the Dean has been particularly 

 unfortunate. The megatherium was, indeed, an enormous animal — 

 mightier than any of the present degenerate inhabitants of the earth ; 

 he lived by tearing down the trees of the forest, and browsing on the 

 leaves and branches ; he was armed with terrific claws, and protected 

 by a skin more dense than that of the rhinoceros ; but, unfortu- 

 nately for the Dean, he was one of the last caught even according to 

 his own hypothesis, and, as we believe, did not exist till ages after, 

 if indeed, he were not coeval with the earlier races of men. His next 

 example, the didelphys, did certainly appear and perish in the oolitic 

 period ; it was, in fact, the earliest warm-blooded animal that existed 

 on the earth, — but what was it ? A little opossum, not bigger than 

 a guinea-pig ! The third is, if possible, worse chosen than the 

 rest — " the pterodactylus ! Why, the pterodactyle was the flying 

 dragon of the ancient world, and would have been far enough 

 above the hills ere a flood could overtake him. For any man 

 so unacquainted with the most familiar facts of our science as 

 to confound together three animals of a different epoch, and so 

 utterly unlike in their physical structure, is itself a portent in the 

 history of geology : nor would such an exposure have been allowed 

 were it not for the considerations before alluded to. As regards the 

 period of time occupied in the formation of the strata, I will mention 

 but a few circumstances. In one part of the oolitic series, we find 

 beds of coralline limestone, separated by a small thickness of clay, 

 and in this clay are multitudes of crinoids, whose bases yet remain 

 fixed to the rock on which they grew : in that little bed of clay is re- 

 presented at least a period of time sufficient for the growth of these 

 animals. In another formation, the lias, I have traced for twenty 



