290 C. SCHUCHERT — LOWEB HELDERBERG-ORISKANY FORMATIONS 



ing directly on the Salina or Waterlime. Beyond the Niagara river, to 

 the northwest of Cayuga, in Ontario, the Oriskany reappears irregularly 



over a very limited area, again overlying the Salina, and is from 6 to V5 

 feet thick. Southerly, along the western side of the Hudson river,#the 

 Upper Oriskany is very intermittent and often but 2 or 3 feet thick. On 

 Becraft mountain there is an outlier of Oriskany. h\ Orange county, 

 the Oriskany again appears to thicken, and in the Neversink valley the 

 thickness is about 125 feet, and at this point it is intimately connected 

 with the Helderbergian. In New Jersey, and particularly in the eastern 

 Appalachian folds of Pennsylvania, the Oriskany in its lithologic char- 

 acter is ever changing from sandy shales, sandstones, and chert beds to 

 coarse conglomerates. Its thickness also increases from north to south ; 

 in northeastern Pennsylvania it is from 50 to 125 feet thick, and on the 

 Lehigh river, below Bowmans, it is fully 200 feet. Continuing south- 

 westerly with the Appalachian folds, coarse grained sandstones predomi- 

 nate. In the region about Cumberland, Ma^land, the Oriskany is said 

 to be 300 feet thick, but probably is much thicker. It is well developed 

 in the vicinity of Monterey, Virginia, but southwesterly, near the state 

 line of Tennessee, the thickness has decreased to 40 feet. Throughout 

 the Appalachian region, from New York to Virginia, it follows upon the 

 Helderbergian, but near the Tennessee state line it begins to rest on the 

 Clinton. 



In eastern Tennessee no Oriskany is known, yet it reappears as a sand- 

 stone with chert beds of about 20 feet thickness in the adjoining counties 

 of Floyd, Georgia, and Cherokee, Alabama. The Oriskany here uncon- 

 formably overlies horizons from the Middle Cambric to the top of the 

 Champlainic or Ordovicic. 



In southwestern Illinois cherty limestones of about 200 feet thickness, 

 followed by a sandstone from 40 to 60 feet in depth, constitute the Oris- 

 kany formation, which is here, as in southeastern New York, intimately 

 connected with the Helderbergian. The Oriskany of Illinois is known 

 along the Mississippi river in three counties, and again appears in western 

 Tennessee as a white chert horizon of about 60 feet thickness. It thus 

 thins out rapidly toward Tennessee, and onl}>' the Lower Oriskany per- 

 sists there with Helderbergian shales and limestones. Elsewhere in the 

 United States the Oriskany is unknown, although the Helderbergian is 

 well developed in Indian Territory. 



In eastern Canada there are two areas of Oriskany outcrops ; typically 

 in the region about Cayuga, Ontario, as previously mentioned, the other 

 area being in New Brunswick, on Campbell river, about Gaspe, Quebec, 

 and about Nictou, Nova Scotia. In Gaspe, it is a limestone formation, 

 and, as in New York and Illinois, is intimately connected with the 



