270 Dr. Bigsby's Sketch of the Topography 



I have visited some of the most interesting localities de- 

 scribed by Mr. Eaton : — as the Mohawk Valley, the Rivers 

 Genessee and Niagara, anid the Excavations at Lockport ; and 

 can so far bear testimony to the fidelity of his observations. 

 The utility, I may be permitted to remark, of certain changes in 

 nomenclature introduced by this gentleman, is very question- 

 able. I have seen nothing to justify the application of the 

 term " grauwacke" to nearly horizontal and usually shaly and 

 homogeneous rocks above the salt-formations, and abounding 

 in organic remains. Whenever they are not strictly argillo- 

 calcareous slates, they are sandstones, with a base of clay or 

 lime. The old words limestone and sandstone seem to me as 

 proper as the "lime-rocks" and "sand-rocks" of Mr. Eaton. 

 If by the appellations "geodiferous," "cornitiferous," &c. given 

 to certain strata, pretty uniform in their situation and charac- 

 ters over a great extent of country, it be only intended to 

 show them to abound in geodes, cherts, &c. they are allowable. 



The rocks forming the basin of Lake Ontario may be enu- 

 merated as follows, beginning from below : 



Gneiss Outlet and N.E. angle. 



White sandstone and conglome- 1 ^^^^^^ ^^^ Macomb's M-. 



rate, quartzy and calciterous J 

 Carboniferous limestone(metallif. 1 t7> . i 



of Eaton) j- l^ast end. 



Metalliferous grauwacke (Eaton) Near Utica, &c. 



Millstone grit (Eaton) Ditto. 



Saliferous and ferriferous sand-1 o ^u i i xt- 



• TT, , X > bouth shore, and JNiaffara. 



stone (Eaton) J ' ^ 



Argillo-calcareous strata (calci- 1 -p.. 



ferous slate of Eaton) j 



Compact limestone, the lower 1 



part full of geodes, the upper > Genessee, Niagara. 



full of chert j 



Calcareous shale (pyritiferous) ... Near Ithaca, and Lake Erie. 



While the gneiss, wherever I have seen it, is at a high 

 angle, these rocks are very nearly horizontal, inclining from the 

 nearest primitive ranges, so as to allow a succession of rocks 

 to appear at intervals in the lake, or in its vicinity at the same 

 level ; the oldest being at its east end, and the newest at the 

 west. They are spread out in close contact (many, if not all, 



360 miles long, and commences near Albany, on the Hudson River. It 

 ascends the valley of the Mohawk, and passing a little south of Oneida Lake, 

 approaches within six miles of Lake Ontario at the River Genessee. From 

 thence, very slowly receding from the latter body of water, it pursues a 

 western course to liuffaloe, at the east end of Lake Erie. 



passing 



