ORISKANY QUARTZITES. 375 



are in the valley south of Greenwood lake and in Pea hill, near Cornwall 

 Station. They outcroj) in characteristic development at a number of 

 points about Monroe, and this name is suggested as an appropriate desig- 

 nation for them. 



The rocks are dark gray to black, fissile to slaty sliales, and they are 

 nearly everywhere fossiliferous. The fossils are usually not numerous 

 nor conspicuous, but they may readily be found by careful searching. 

 These slates were considered " Hudson River " in age for many j^ears, 

 and they are not unlike the Hudson slates in general appearance. In 

 1886 Britton and Merrill ascertained definitely tliat the shales in the area 

 west of Green Pond mountain were Lower Devonian, as they overlaid 

 the Oriskany grit. Onh' one fossil was found by these observers, a 

 Palasoneilo, of Upper Devonian liorizon, according to Professor James 

 Hall, but it added much weight to the structural evidence. During the 

 past few years I have obtained f(^ssils from many localities along the 

 GreeuAVOod lake valley and all around the lower slopes of Skunnemunk 

 mountain. Professor James Hall kindly examined them for me and he 

 finds that they are typical lower Hamilton (group) species. The most 

 prolific localities I found were along the shore of Greenwood lake, along 

 the roadside two miles due west of Monroe, and at Pea hill, a mile south- 

 west of Cornwall Station. 



Orhkany Quartzites. — In 1886 Britton and Merrill discovered fossilifer- 

 ous Oriskany beds at Newfoundland and at several points to the south- 

 west. I find that the formation also occurs at intervals northward along 

 both sides of the Devonian belt, but it is much less fossiliferous. 



The best exposure about Newfoundland is that described by Merrill 

 which is just south of the turnpike on the southern and eastern slopes 

 of the first ridge west of Kanouse mountain. This is about 750 yards 

 cast-northeast of the depot. The ridge is heavily drift-covered and there 

 are only a few small outcrops, but the}' are quite abundantly fossiliferous. 

 Spirifer arrectas is the most conspicuous fossil, but, as noted by Merrill, 

 there are many casts of other brachiopoda, apparently including Rcmsel- 

 Iferia, and cyathopylloid corals. The rock is in greater part a light- 

 colored quartzite containing quartz grains and pebbles. Some portions 

 are calcareous and weather t(^ a loose grit, and it is mainly in these that 

 the fossils are exhil)ited, 



Merrill mentions another localitv of the rock south of Newfoundland 

 depot, but here the fossils are not so well preserved. Along the western 

 slope of the Green Pond mountain and the northern and eastern foot of 

 Bowling Green mountain there are occasional exposures of the grit, and 

 there is a small mass of it on the east side of Green Pond mountain at 

 Middle Forge. The thickness in the Newfoundland region and south- 



LlII — Boll Geol Soc. Am., Vol. 5. 1893. 



