144 GEOLOGY. 



these occasional substitutes I am enabled to sijI* • 

 ^lount to a certain extent, the want of a chemical 

 apparatus, when I travel at a considerable dis» 

 tance from my lodgings. With my slender ma- 

 terials for investigation, I have, however, been 

 been enabled to ascertain the great geological 

 outlines of this region. The country about eight 

 miles south of the Cayuga Bridge, and both east 

 and west, is composed of argillaceous schist, or 

 clay slate. To the north, the great lime stone 

 ledge commences, which dips to the south, and 

 which tbrms the dam of the Cayuga and the other 

 minor lakes, and which wpholds Lake Erie. This 

 great calcareous ledge is interspersed with all the 

 species and varieties cf that substance, and with 

 salt, sulphur, carburetted hydrogen, and bituminous 

 springs — with gypsum, hydraulic lime stone, 

 magnesian lime stone, fetid carbonate of lime, 

 blue lime, shell lime, silicious lime, with nodules 

 of flint, he. in stratified and scattered portions. 

 And the substratum of the calcareous and schis- 

 tous formations, is, as far as I can trace it, a com- 

 pact sand stone, generally of a red color. 



I found tlie upper and middle stratum of the 

 great cataract of Niagara to consist of fetid car- 

 bonate of lime, commonly called stink stone, or 

 swine stone ; and the inferior stratum of a com- 

 pact, stratified red sand stone, which strikes fire 



