65 
America, but most abundantly in the black transition 
limestone, in the northern section of the country. 
The richest locality, not only of this genus, but also 
of the Calymene and the Asaph, is Trenton Falls, 
on West Canada Creek, about 13 miles to the north 
of Utica, in the state of New York. The following 
extracts from the notes of Professor Renwick, which 
accompany Dr. Dekay’s account of the Isotelus, will 
give some idea of this vast depository of the medals 
of ancient zoology. West Canada Creek, is one of - 
the principal branches of the Mohawk River. At 
Trenton Falls it has worn itself a passage through 
the rock for the distance of nearly two miles, forming 
a series of water falls; and has thus laid open to view 
the strata to the depth of probably 300 feet. The 
layers of the rock thus disclosed are nearly hori- 
zontal, and of various thicknesses: they are composed 
of limestone, with the exception of numerous thin 
veins of argillaceous matter. The higher strata are 
composed of carbonate of lime nearly pure, of a light 
grey colour and crystalline structure. At greater 
depths it is more compact and darker in colour, and 
finally it appears quite black and highly foetid.* * 
Animal remains are contained in every part of the 
rock; besides several genera of trilobites, we have 
several species of orthoceras Encrinites and Fun- 
gites—Nautili—Terebratule and Producti, are quite 
common. The favosites here are sometimes six 
inches in diameter, and in such numerous columns, 
* See Annals of N. Y. Lyceum, vol. i. page 185. 
, ¥2 
* 
