GEOLOGIC FORMATIONS OF NEW YORK 161 



the line of outcrop of the Onondaga and Oorniferous limestones 

 as before described, are nearly destitute of this useful rock; being 

 formed of vast deposits of slaty, shaly, and sandy strata, several 

 thousand feet in thickness, the exposures of which extend south- 

 ward from a few miles south of the Erie canal to beyond the 

 Pennsylvania line. 



These rocks give rise to peculiarities in the topographic feat- 

 ures of the country which they underlie, and in its soil and 

 vegetable productions. Containing little lime, the culture of 

 wheat does not generally succeed well upon them; nor does the 

 central wheat growing district extend over them for more than 

 a few miles south of the limestone range, except in a few alluvial 

 valleys, or places where calcareous materials from the limestone 

 belts have been strewed over the southern shales by glacial 

 action, of which we shall speak hereafter. Grazing and dairying 

 are almost exclusively the pursuits of the farmer. 



The most marked physical features of this great extent of 

 country are its deep valleys and long hills, usually extending in 

 a north and south direction, as an inspection of any map will 

 show. Some of these long north and south valleys dam- 

 med by drift deposits are the basins of that remark- 

 able series of lakes beginning with Otsego, and com- 

 prising Canaseraga, Cazenovia, Otisco, Skaneateles, Owasco, 

 Cayuga, Seneca, Crooked, Canandaigua, Honeoye, Canadice, 

 Hemlock, and Conesus; all so similar in general form and 

 direction, and in the shape and geological formation of their en- 

 closing hills. Over the whole extent of these rocks, the country 

 is ' rolling,' or broken into ridges generally running north and 

 south, and rising from one to eight hundred feet above the main 

 valleys; and it is rarely that we find among them a plain half 

 a mile wide, except in a few of the ' bottom-flats ' or alluvial lands 

 along the larger rivers, such as the Genesee. 



These rocks are generally quite uniform in their character, 

 especially in the eastern part of the state near the Hudson valley, 

 and might be grouped into one enormous formation 5,000 feet or 

 more in thickness, except for a few variations in texture, and 



