GEOLOGY OF THE WATKIXS AND ELM IRA QUADRANGLES II 



Cashaqua shale. In the Waggoner gully near the village of Poultney 

 it is i foot. 6 inches thick in two or three layers and 15 feet below 

 the top of the Cashaqua shale. In a small ravine west of Gibson's 

 landing on Keuka lake it is 2 feet, 6 inches thick in four uneven 

 nodular layers, separated by shale. The subdivision of the limestone 

 into layers and the thinning out of that part of the Cashaqua shale 

 above it continues to the Big Stream gorge near the north line of 

 this quadrangle, where it is exposed west of and about 50 feet below 

 the Northern Central Railroad. Here it consists of seven thin layers 

 of concretionary limestone, separated by shale, the entire band hav- 

 ing a thickness of 5 feet and it is overlain by the black Rhinestreet 

 shale, the intervening light shales having thinned entirely out. The 

 horizon is exposed in the Rock Stream gorge, ^2 mile farther 

 south but here the layers are less distinct and some of them have 

 disappeared. In Glen Eldredge on the east side of the lake 3 miles 

 north of Watkins but one layer of limestone appears, though the 

 adjoining shales are quite calcareous. In its western outcrops, 

 specially in the Naples valley this rock is singularly profuse in 

 goniatites and other cephalopods. It is there more conspicuously 

 than here tinted with shades of red and green. The only species 

 observed in it on this quadrangle are Buchiola speciosa, 

 P h r a g m o s t o m a n a t a t o r , M a n t i coc e r a s patter- 

 s o n i , C h o n e t e s 1 e p i d 11 s , Lingula sp. The horizon is 

 shown not only at the points mentioned but also in the Big Stream 

 gorge at 620 feet A. T. ; in Watkins, Montour Falls, Havana, 

 Eldredge and Excelsior glens at 630 feet A. T. 



Rhinestreet shale 



This is a mass of black compact shale which attains a thickness 

 of but 10 to 12 inches. Like the Parrish limestone the formation is 

 not known east of the Seneca lake valley. It increases in thickness 

 toward the west at the average rate of nearly 2 feet a mile and on 

 the shore of Lake Erie it is 185 feet thick. In the Genesee river 

 gorge and westward it carries thin beds of lighter colored shale and 

 rows of large septaria. It is exposed at the same points as stated 

 for the previous formation. On this quadrangle the Rhinestreet 



