302 ('. scirrciIKKT — LOWER lIKLhKlinKRiJ-OKIsKANY FORMATIONS 



In the second district, Emmons did not Observe this formation, and 

 in the fourth district it is not well developed. Hall* writes that the 

 Oriskany — 



" Where best developed in the fourth district, is a coarse, rather loosely cemented, 

 purely silicious sandstone, of a yellowish white color. It contains some flattened 

 nodules of chert or flint. ... In the upper part of the lock are numerous 

 concretions of dark colored or nearly black compact crystalline sandstone, very 

 hard and tough. ... In Monroe county, its only representative is a layer of 

 greenish conglomerate, about 4 inches thick. , . . At one or two other points 

 it appears as a coarse sandstone of a few inches in thickness, resting on the Onon- 

 daga salt, group. The last place in the district where it has been noticed is in the 

 bed of Black creek at Morganville, in Gi nesee county." 



The Oriskany sandstone in New York "is not more than 30 feet, and 

 usually much less/'f This, of course, does not refer to southeastern 

 New York, where this formation is much thicker. 



The Oriskany formation is best developed in southeastern New York, 

 in Orange count}'. 



" The western belt forms the western part of the Helderberg ridge, which ex- 

 tends up the Neversink valley from Pork Jervis, New York. It consists of fine- 

 grained shaly sandstones and impure limestones, the latter often containing many 

 fossils. . . . There are also present cherty bands containing fossils. The 

 Oriskany forms narrow ridges, and the thickness of the formation is about 125 feet. 



"The second [or eastern] Oriskany area is along the western side of Bellvale 

 and Skunnemunk mountains, where it affords a fine grained red or gray quartzite 

 which changes locally to a conglomerate. . . . About 100 feet are exposed." t 



Doctor S. T. Barrett, living for man) 7 years at Port Jervis, studied the 

 outcrops and collected the faunas of the Niagaran, Helderbergian, and 

 Oriskanian formations of this region. In 1876 § he published his results, 

 and from these it is learned that the Upper Pentamerus or Becraft passes 

 without break into the Oriskany. The Oriskany is here not less than 

 100 feet in thickness, while " it is probably more, the higher arenaceous 

 layers' of this division having been removed." 



The fauna collected by Barrett from this horizon consists of the fol- 

 lowing : 



Orbiculoidea jerrensis (Barrett). Diaphorosloma ventricosa (Conrad). 



Eatonia peculiaris (Conrad). Platyceras gebJtardi (Hall). 



Spirifer nrenosus (Conrad). Aciinopteria texlilis arenaria (Hall). 



Spirlfer mnrckis >ni Castelnavi. TentacuHles elongalus Hall. 

 Rensselssrm oroides (Eaton). 



*Geol. N. V., part iv, Survey Fourth l>i*t., is4;s, pp. 146-150. 



tllull ■ Geol. N. V.. Survey Fourth Dist.. 1843, p. 147. 



X Heiurich Hies: Fifteenth Ann. Rept. state Geol. N. Y., 1897 [1898], p. 402. 



i Ann. Lyc. Nat. Hist. N. V., vol. xi, 1876, pp. 293, 294. 



