WITH THOSE OF NEW YORK. 291 



we know not, but they are — still, who can say what changes may 

 occur, or whether any exist in the depths a thousand miles- from 

 land ? From the nature of sedimentary deposits it can be only 

 the finer parts that ever reach to great distances from their origin ; 

 and, reasoning thus, the fauna of the deep and distant parts of the 

 ocean, if any exist, would be uniform, not being liable to destruc- 

 tion or change of condition from the rapid invasion of variable 

 deposits like those near the shore. The deposition of a coarse 

 sandstone or conglomerate succeeding to a shaly mass, would in 

 all probability destroy the greater number of living forms as far 

 as it extended. But at the same time, the finer materials produ- 

 ced by the same cause, would extend far beyond the limits of the 

 coarser, and thus approximating in some degree to the low^er mass, 

 the fossils might be continued long after they wxre destroyed at 

 another point. 



One of the most interesting changes in the products on going 

 westward, is the great increase of carbonate of lime, and the 

 diminution of shaly and sandy matter, indicating a deeper ocean 

 or greater distance from land. The source of the calcareous de- 

 posits is thus shown to have been in that direction, or in the south- 

 W'Cst, while the sands and clays had their origin in the east, south- 

 east, and northeast, producing a turbid condition in the waters 

 of these parts during long intervals, which w^as unfavorable to the 

 production of calcareous matter, and the formation of chemical 

 deposits. In New York we are evidently upon the margin of 

 this primeval ocean, as indicated in the character of the deposits 

 as w^ell as organic remains ; the southwest unfolds to us that por- 

 tion where greater depth and more quiet condition prevailed. 



Note. In the paper published in the American Journal of 

 Science, I inadvertently said, that the Catenipora was found only 

 in the Niagara limestone, though I had previously obtained it 

 from the Clinton gi'oup, but from its character I was inclined to 

 refer it to a different species from the C. escharoides. The two 

 are however identical, presenting no greater differences than are 

 often seen in this fossil from the same rock and locality. Not- 

 withstanding this fact, however, the Catenipora is far from being 



