Bishop — Geology of Erie County. 



311 



The Salina Group. 



The rocks of this group are not well exposed in Erie comity, the besl 

 section being found in Genesee county, east of Erie county, where the 

 Tonawanda creek crosses the outcrop of Corniferous and upper Salina beds. 

 The creek here breaks over the edge of the Corniferous limestone and 

 hydraulic limestone, forming the Indian falls, .lust below the fall, the rock is 

 a thick-bedded limestone containing nodules of gypsum and weathering with 

 a cavernous, irregular surface. Below that, the rock is shale, mostly gypseous 

 in character, sometimes reddish, but more often grey or bluish. On the 

 Indian reservation, near the mouth of the ravine, a limited amount of gypsum 

 is quarried, blue-grey or mottled in color and of fair quality. About half a 

 mile above the West Shore railroad bridge is an outcrop of red and grey 

 gypseous shales which continue through the reservation to the iron bridge 

 near the Indian church. Below this is a stratum composed of hard, thin- 

 bedded calcareous rock, containing minute lenticular cavities and casts of 

 crystals. The rock exposure extends about 200 yards below the bridge. 



Within the limits of Erie, county, the Salina rocks are mostly covered 

 with drift. The most complete section is found in the bed of Murder creek 

 at Akron. From Falkirk down to Main street are the water-lime rocks. 

 Below the railroad bridge, shales crop out in the bed of the creek for two 

 miles or more. The thickest exposure of these showed three feet of light- 

 colored calcareous shale, weathering to light pink, beneath which were four to 

 six feet of harder, greenish shale. A small exposure of shale is reported in 

 the same creek opposite the end of the road leading east to the Indian reser- 

 vation, but I was unable to visit it. 



An outcrop of thin-bedded hydraulic limestone occurs on the farm of 

 Martin Racquet, about one-half mile south of East Amherst near the Transit 

 load, where it is used for macadam. 



On Grand Island there are two outcrops. The more northerly is at 

 Edgewater, about 200 yards below the boat-landing. The rock here is: 



(1) Black shale in the river-bed. 



(2) Greenish shales containing nodules of gypsum, one and one-half feet. 



(3) Light-colored, soft, friable gypseous shales, five feet. 

 The exposure extends 300 yards down the river-bank. 



The other outcrop is at the extreme southern end of the island, where 

 the river separates into two channels. The rock is a thin-bedded, impure 

 limestone, weathering like the waterdime, and containing minute lenticular 

 cavities. Fragments of such lock are plentiful in the drift about Buffalo, 



