22 RURAL NEW YORK 



Niagara formation capped by a bard magnesian lime- 

 stone tbat forms tbe floor of tbe Niagara River and 

 over wbicb its cataract drops. Tliis cap of bard 

 limestone, underlain by tbe soft Lockport sbale, con- 

 stitutes tbe rock structure tbat gives rise to tbe mag- 

 nificent Falls of tbe Niagara. 



In tbe period succeeding tbe formation of tbe 

 Niagara limestone, western New York was a sbal- 

 low arm of tbe sea witb a desert climate. In tbis 

 sea tbere accumulated witb tbe mud tbat now makes 

 tbe Salina sbale, great beds of salt and gypsum. It 

 forms a band of country five to twenty miles in width 

 as far east as Rome. At Syracuse, wbere salt springs 

 originally occurred, salt is extensively manufactured, 

 from which fact tbe name " Salt City " is taken. 

 These springs were valuable to tbe Indians as well 

 as to the early settlers and account for the begin- 

 ning of tbe city of Syracuse. At Ithaca, Watkins 

 and points in tbe Genesee Valley, these salt deposits 

 are reached by wells and shafts extending through 

 the later rock formations for commercial working. 



The next and one of tbe less important limestone 

 formations. I lie Helderberg limestone, lies above and 

 south of tbe Salina. It is blue rock high in cal- 

 cium content witb tbick bedding. Its outcrop is not 

 wide but it reaches from near Buffalo, eastward 

 around tbe east base of tbe Catskill Mountains. It 

 passes by LeRoy, Geneva, Auburn, and has an even 

 M'ider development in southern Oneida and Herkimer 

 counties and tbe northern part of Schoharie County. 



Tbe position and extent of these various limestone 



