Luther — Geology of the Salt District. 



203 



of country that expands in the western part of Oneida county and occupies a 

 considerable area in the southwest part of Lewis county, nearly the whole of 

 Oswego county, and a belt along the shore of lake Ontario that varies in 

 width from one and a half miles in Wayne county, to eleven miles in Orleans 

 and Niagara counties. 



Clinton group. This next division in upward succession embraces strata 

 of such a diversified character that it was designated by Vanuxem the 

 " Protean group." 



In Mongomery, Herkimer and Oneida counties the Clinton rocks are from 

 100 to 200 feet thick, and include thick beds of greenish grey and red sand- 

 stone, and of green and blue-black shales. The sandstones are sometimes 

 slightly calcareous ; two beds of lenticular argillaceous iron ore are inter- 

 stratified with them. 



In the western counties the rocks are less arenaceous, and limestones of 

 considerable thickness occur. 



In the gorge of the Genesse river at Rochester, the section is as follows, 

 from below upward : 



Green shale, sandy and harder toward the bottom, and containing a 



bed of iron ore near the top - - - - - - - 24 feet. 



Limestone with shaly partings, and one foot layer of fossiliferous 



iron ore 14 feet. 



Green clayey shale, in which an irregular layer of fossils known as 



the " pearly layer " occurs 24 feet. 



The " upper limestone " composed of alternating thin layers of lime- 

 stone and shale - - - - - • - - 18 feet. 



Making the total thickness of the Clinton formation at that locality 80 feet. 



On Niagara river, the lower green shale has decreased in thickness to 

 four feet and the second bed of green shale has disappeared, the limestones 

 meeting and becoming one bed, twenty-five feet thick ; the whole group 

 having been reduced to two beds which aggregate twenty-nine feet. 



The Clinton beds are the surface rocks over a narrow belt beginning at 

 a point in Montgomery county and extending westward on the south side of 

 the Medina sandstones to the western border of the state. 



The belt is about eight miles wide in the vicinity of Oneida lake, which 

 lies entirely within it. This is its greatest width. West of Cayuga county 

 it is less than two miles wide. 



