Ct)NSISTENCY OF GEOLOGY WITH BACKED HISTORY. 397 



doubt that the animals received their existence, and lived and died 

 in the ocean, and that, at least at the time of their death it was full 

 of calcareous carbonate either in solution or in mechanical sus- 

 pension, or both.* When they died, they of course subsided to the 

 bottom, and were surrounded, as they lay, by the concreting calcare- 

 ous matter. Multitudes of them were present, at the same time and 

 place, in all the confusion of accidental position, and therefore were 

 enveloped, just as we find them, in every imaginable posture ; the in- 

 terstices were filled by the calcareous deposit, and this being more or 

 less chemically dissolved, produced a firm sub-crystalline mass, a sec- 

 tion of which shews us the animals sawn through, and admitting of a 

 polish, like the rest of the rock. 



If we could suppose that our common clams and oysters, that lie 

 in the mud of our harbors and inlets, were to become solidified into 

 one mass, along with the matter which envelopes them, the case would 

 not be dissimilar ; only they would be enveloped in earthy, instead of 

 crystalline matter, and the rock formed from it would be referred to 

 the most recent secondary, or to the tertiary, unless its texture were 

 afterwards altered by igneous or other agencies. 



It is easily understood, also, how a new stratum, either of the same 

 or of diflferent constitution, may be deposited upon a previous one ; 

 and with it, the bodies of the animals that lived and died in the fluid ; 

 and these might be the same animals with those of a previous stratum, 

 or of a different species or genus, it being understood that, in the case 

 of marine animals, each successive stratum was, in its turn, the bot- 

 tom of the then ocean, and also the upper or last consolidated layer 

 of the crust of the earth, as it then was at that place. f 



As we have no direct historical evidence to the facts, it is impossi- 

 ble to say, precisely, what circumstances would determine the waters 

 to deposit, different things at difl?erent times, for instance at one peri- 

 od, a stratum of limestone, with madrepores and encrinites, and at 

 another, one of breccia or sandstone, with bivalve or univalve shells. 



With respect to marine and aquatic animals, the waters appear to 

 have been, at diflferent periods, adapted to the support of diflferent ra- 

 ces, and thus their remains became successively solidified ; not imply- 



* The eruption of a vast calcareous sediment, by submarine igneous agency, 

 which some have supposed in the case of chalk, is hardly admissible here, as the 

 transition limestones does not corresponds with the usual appearance of mechan- 

 ical deposits. 



t A similar course of reasoning, will apply to fresh water deposits. 



