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NEW YORK STATE MUSEUM 



quadrangles and 15 feet on the western. In the exposure of this 

 horizon in the Big Stream ravine it rests directly upon the Parrish 

 limestone, but westward across thiese quadrangles a rapidly thick- 

 ening bed of light shales intervenes and on the west side of Keuka 

 lake it is 20 to 25 feet above that limestone and in the Naples valley 

 50 feet above it. 



East of the Genesee valley this formation is composed almost 

 entirely of densely black bituminous shales, but farther west it 

 includes several layers of lighter shales that contain a few of the 

 fossils of the Cashaqua shales and rows of large spheric concretions. 

 Fossils are exceedingly rare in the black shales but beds of land 

 plants forming thin seams of lignitic coal are seen occasionally. 



The following species have been identified from the Rhinestreet 

 shale in this vicinity. 



Paleoniscus devonicus Clarke Spathiocaris emersoni Clarke 



Acanthodes pristis Clarke Lunulicardium velatum Clarke 



Polygnathus dubius Hinde Pterochaenia fragilis Hall 



Prioniodus spicatus Hinde Leptodomus multiplex Clarke 



P. erraticus Hinde Lingula ligea Hall 



The Rhinestreet shale is well exposed in the ravine at Friend; 

 in the Belknap gully at Guyanoga; in the Wagener ravine at 

 Pulteney; at 1000 feet A. T. in the small ravine 1 mile east of 

 South Pulteney ; in the Urbana ravine ; along the lake shore south 

 of Oak point and along the east side of the lake opposite Hammonds- 

 port, also in the Rye Point and other ravines farther north to Grove 

 Springs. 



In the region between Grove Springs and Crosby the Cashaqua 

 shales and the lower beds of the Hatch flags and shales have an 

 unusually large proportion of bituminous matter and the Parrish 

 limestone does not appear. This condition together with con- 

 siderable undulations of the strata makes identification of the 

 horizon of the Rhinestreet bed somewhat uncertain, but its position 

 is, approximately at least, as indicated on the map. 



Some of the best exposures of the Rhinestreet shale west of these 

 quadrangles are along Rhinestreet and in Parrish gully at Naples; 

 in Buck Run ravine at Mt Morris and in the Genesee River gorge 

 in Smoky Hollow ; in the ravine at Griswold 6 miles west of Attica ; 

 in the Eighteen Mile Creek gorge at North Evans; and along Big 

 Sister creek below Angola, Erie county. 



The limits of the remaining formations shown on this map, though 

 well defined on the Naples quadrangle, are very obscurely so on the 

 Hammondsport and Penn Yan quadrangles. 



