DESCRIPTION OF THE FORMATIONS. F\ 4? 



vestigation is required before any real correlation can be 

 established, yet the following comparison between the Clin- 

 ton in New York and in Pennsylvania may not be without 



interest : 



New York. Perry County, Pa. 



Limestone. Fossil ore and limestone. 



Sand rock. 

 Iron ore. Fossil ore. 



Sand rock. 

 Upper green shale. Upper green shale and ore. 



Iron ore and limestone. Iron sandstone and fossil ore. 



Lower green shale. Lower green shale. 



Thickness, 80 feet 6 inches. Thickness, 989 feet. 



Difference of opinion may prevail as to the identity of 

 the beds of iron ore but this is of little moment. They are 

 usually discontinuous and probably their horizons vary. 

 But it is impossible not to notice the close correspondence 

 in general between the two sections. No sandstone appears, 

 it is true, in New York, and little limestone in Pennsylvania ; 

 but such discrepancies must be expected, and are due to 

 difference of conditions during deposition. They are no 

 argument against correspondence. 



The reduction of the mass of the so-called Clinton group 

 in Perry county brings it into close correspondence with 

 the typical beds in New York. There is nothing in the 

 New York Clinton like the great mass of red shale and the 

 overlying equally thick mass of variegated shale which oc- 

 curs in Pennsylvania. 



The Clinton Lower Green Shale. 



The solid mass of smooth, thin-bedded green shale is 

 persistent along the outcrop, but very few opportunities are 

 afforded for measuring its thickness or estimating its vari- 

 ation. Its upper portion is often exposed, but its lower 

 beds are seldom seen, and its contact with the Medina is 

 visible nowhere in the county to my knowledge. 



These shales contain numerous thin beds of a red sand- 

 stone closely resembling the iron sandstone, of which they 

 were the geological precursors. They are scantily fossil - 

 iferous, but time would doubtless enable the geologist to 

 obtain a fair collection of species. Their exposures are 



