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NEW YORK STATE MUSEUM 



At the falls and in the ravine above, about 100 feet of black 

 Rhinestreet shales are exposed. 



A row of very large septaria, occurs in the black slates 28 

 feet above the top of the Cashaqua shales. 



The Middlesex shales and the base of the Cashaqua shales 

 are exposed in the bed of Ellicotts creek, 1% miles west of the 

 Erie Railroad station at Darien. 



The bottom of the Cashaqua shales is level with the rails 

 on the bridge. This is the most northern exposure of Portage 

 strata in this State. 



On Cayuga creek an outcrop at Iron Bridge Mills shows the 

 Styliola limestone and 12 feet of Upper Genesee blue black 

 shales above it. 



At Cowlesville, 2y 2 miles south, there is a large exposure 

 of the Cashaqua shales in the cliffs along the stream, and the 

 Rhinestreet shales with many large septaria outcrop almost 

 continuously below and above Folsomdale. 



At and above the forks at Cayuga creek, 3 miles south of 

 Folsomdale, the top of the Rhinestreet shales and about 100 

 feet of blue shales, in which thin layers of black slates and 

 a few flags are intercalated, are exposed. 



On Buffalo creek the upper part of the Cashaqua shales is 

 exposed in the escarpment along -the west side of the stream 

 below the bridge at East Elma. Fifteen feet of black slates 

 crop out iy 2 miles up the stream, and at Porterville 100 feet 

 of the Rhinestreet shales are exposed, in which two rows of 

 very large septaria, separated by 35 feet of black slates, occur. 

 Some of the septaria are 8 feet in diameter and 2 to 2% feet 

 thick. 



Al Johnson Falls, 7 miles up the valley southeast from Por- 

 terville, a small creek comes into the valley from the east over 

 a high cascade and through a short but deep ravine. 



There are G2 feet of Gardeau shales and flags exposed below 

 the falls, and 144 feet in the face of the cascade and at the top. 



The beds are principally soft bluish shales with flags and 

 thin sandstones, that arc more frequent and thicker toward the 

 top. 



