PORTAGE AND NUNDA QUADRANGLES 67 



original employment of the name and we here cite the explanation 

 of the term as first used by Professor Hall, taken from the Third 

 Report on the Fourth Geological District, 1839, pages 322-24: 



'The tops of the hills and high grounds in the towns of Erin, 

 Veteran and Catlin, display a grouo of rocks and fossils very 

 distinct from those last described. The essential difference is the 

 lithological characters of the sandstone of this group in the absence 

 of argillaceous matter in most of the layers, these being nearly a 

 pure silicious rock, harsh to the touch, and generally of a porous 

 texture ; while still a large proportion of the mass consists of com- 

 pact shales and argillaceous sandstones of a softer texture than 

 those below. The surface of the sandstone layers is rough, while 

 those below are smooth and glossy, and being never rippled, prove 

 that the rocks were deposited in a quiet sea." 



In the previous chapter we have referred to an already recognized 

 necessity of removing from the Chemung division of the Genesee 

 valley a lower portion which Professor Hall himself anticipated 

 might have to be excepted therefrom on stratigraphic grounds only. 

 With the Wiscoy beds eliminated there remains thereabove in this 

 section 400 feet of sandstones and shales, not differing greatly from 

 the Portage beds in appearance nor lithologically, though the sand- 

 stones are usually light olive-gray in color and more micaceous. 



Thin layers of impure limestone resulting from aggregations of 

 brachiopods and other fossils occur occasionally in the sandy layers 

 but are most common in the upper beds. The shales are in all 

 variations and shades of color from light blue gray and olive to 

 deep black. Rows of small calcareous concretions occur in some 

 of the lighter shales, and larger, but less clearly defined masses of 

 concretionary character are in a few of the heavier sandstones. 



The stratum containing brachiopods at Long Beards Riffs and 

 Wiscoy falls is in the lower part of a band of sandstones and shales 

 exposed at Mill's Mills and along East Koy creek, a mile north of 

 Lamont. Soft shales prevail in the succeeding 400 feet of strata 

 though there are several lentils of sandstone embraced in this part 

 of the section. Exposures of this horizon in the vicinity of Pike, 

 show mostly light shales that become rusty on exposure between 

 thin rough flags 1 to 3 feet apart. In the Dingman quarry 1 mile 

 north of Pike a 12 foot band of sandstones is exposed that is about 

 200 feet higher in the strata than the Long Beards Riffs lentil. 

 These sandstones are also exposed along the Allegany road a mile 

 southwest of Pike, where one of the layers contains a calcareous 

 mass of fossils and after long exposure weathers dark brown. 



