428 New York State Museum 



The Pennsylvanian system is represented by the Olean 

 conglomerate and Sharon shale of Pottsville age. The 

 Olean conglomerate (Lesley '75) is a massive round- 

 pebbled conglomerate, varying quite rapidly in texture 

 both horizontally and vertically and with a thickness of 

 50 to 90 feet. It is widely known because it forms the 

 "Rock City" southwest of Olean in Cattaraugus county 

 (figure 60). Here, as at Little Genesee and a few other 

 places in southwestern New York, it caps the highest hills 

 (just north of the Pennsylvania state line). Plant re- 

 mains of Pottsville age are found in this bed. Overlying 

 the Olean conglomerate at "Rock City" is a very small, 

 thin patch of sandy, ferruginous shales, the Sharon shale 

 (Rogers '58). A thin coal bloom in connection with this 

 was reported some years ago as disclosed in grading a 

 road, indicating a thin streak of coal in the shale, but 

 no coal of value need be looked for in New York. This 

 shale is the highest member of the Paleozoic system in 

 New York State. 



The Fossils. As pointed out above some of these post- 

 Devonic beds in New York State are fossiliferous, others 

 are practically barren. Chemung types continue into 

 these beds and Mississippian types appear. A study of 

 the fossil faunas of the Olean Quadrangle (Butts '03) 

 has brought out the fact that of 128 species collected 60 

 species occurred below the Wolf Creek conglomerate 

 only, 59 species above the same horizon only. The char- 

 acteristic fossils of this formation in this area are species 

 of the peculiar pelecypod genus Ptychopteria elsewhere 

 unknown. The brachiopod Oehlertella pleurites ranging 

 through the Cattaraugus occurs also in the Cuyahoga for- 

 mation of early Mississippian age in Ohio (Butts). The 

 brachiopod Camarotoechia allegania is highly characteris- 

 tic of the Oswayo shales. 



