EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA 135 



Oriskany material from Cumberland, Md. on which Hall based many of his 

 original descriptions. At Pine Hill near Highland Mills the rock is a sand 

 residuum without any calcareous cores even where exposed in a deep rail- 

 road cut, but it evidently has had a considerable lime content. In the Port 

 Jervis section the Oriskany is a black limestone with its fossils in part silici- 

 fied, and this is the character of rock that prevails in the extension of the 

 horizon into New Jersey with sandstones lying at the top. Weller gives 

 the Oriskany a thickness of 170 feet in New Jersey and speaks thus of the 

 rocks : " These beds are for the most part silicious limestones, but at the 

 summit of the formation in the southern half of the Wallpack ridge in New 

 Jersey the higher beds are replaced by sandstones. With the southwestern 

 extension of the formation into Pennsylvania the arenaceous facies becomes 

 more and more conspicuous, the sandstones replacing lower and lower beds 

 until the entire Oriskany formation is a sandstone continuous with the Storm- 

 ville sandstone or conglomerate [N. J. Geol. Sur. Rep't. Pal. 3. 1903. P-93J. 



Some authors have been ready to find a basis for subdivisions of the 

 Oriskany in this difference in the character of the sediment. Personally I 

 have not felt constrained by this evidence. In the typical and highly fos- 

 siliferous Oriskany sands of central New York all trace of calcareous 

 deposit is wanting and these sands have transgressed westward on a much 

 eroded bottom of Helderberg limestones. The species of these sands are 

 not particularly common in the more calcareous deposits of the east but 

 none is absent. The western sands are the transgressing shore deposits of 

 a late stage of Oriskany time. Were the limestones and sandstones always 

 present in the eastern sections, even without variation in fauna they would 

 form a stable basis for stratic division, but one or the other may be entirely 

 absent from the section or the relations of the two quite inverted. 



Dr Weller divides his Oriskany sections into three zones, Mr Shimer 

 the Port Jervis section into two, Mr Chadwick designates the conglomerate 

 beds at the base of the section near Rondout as the " Connelly conglome- 

 rate," the overlying limestone with its abundant fauna the " Glenerie lime- 

 stone " and suggests the term "Port Jervis limestone" for Shimer's lower 



