362 Review of the New York Geological Reports. 



At Frankfort, Kentucky, a rock of a very similar aspect oc- 

 curs and is quarried extensively for tombstones. Mr. Vanuxem 

 considers it identical with the Birdseye limestone of New York. 



The lower magnesian limestone of the Wisconsin River, inter- 

 posed between the sandstone and fossiliferous limestone already 

 referred to, and containing oolitic layers, is most probably the 

 equivalent of the Black River limestone or the calciferous sand- 

 rock. 



Trenton Limestone. — (No. 2 of Pennsylvania and Virginia 

 Reports.) No rock of the New York system seems to be better 

 characterized than this, and none affords a richer harvest to the 

 palasontologist. The inferior rocks, we have seen, furnish occa- 

 sionally organic remains, but they are ievx and far between, and 

 for the most part obscure ; but here the catacombs of an entomb- 

 ed world of animated existence suddenly bursts upon our view ; 

 not mutilated, dispersed and unintelligible, as one might expect, 

 considering the date and condition of the deposite, — but standing 

 out in bold relief, even detached and complete, with the minutest 

 details of organization preserved in all the perfection of life, in- 

 viting us to the contemplation and study of the anatomy and 

 physiology of races, the aborigines of this terrestrial globe, and 

 leading us thence to deduce inferences regarding the condition of 

 our earth at this remote palaeozoic period. The western exten- 

 sion of this and the overlying beds of the Champlain divisions, are 

 indeed but a calcareous aggregation of Mollusca and Polyparia, and 

 have furnished to the cabinets of the curious a greater variety of 

 fossil specimens, and more prolific subject for the research of the 

 naturalist, than any of the superincumbent, more recent forma- 

 tions. 



The Trenton limestone in New York is, for the most part, a 

 dark or black fine-grained limestone in thin layers, separated by 

 beds of black slate. It passes also into a grey, crystalline lime- 

 stone, particularly the upper beds ; and then affords a good mate- 

 rial for architectural purposes. The black variety is usually too 

 shaly to be a durable building rock, but where it is free from ar- 

 gillaceous matter, as in some localities, it is compact, and then sus- 

 ceptible of a good polish. 



The organic remains peculiar to this formation, which have the 

 widest range, are here represented. 



