LAKE ESCARPMENT MORAINES. 671 



the Genesee River seems to have been southeastward to the Canisteo River, 

 a tributary of the Susquehanna, through the Burus-Arkport channel, brought 

 to notice by Fairchild.^ An outhne of this hue of discharge, given by 

 Fairchild, is as follows.^ 



When the ice uncovered the region of Portageville the Genesee waters found 

 an avenue of escape, 150 feet lower than Cuba, over the morainic dam east of 

 Portageville and tilled the Upper Nunda (Kishawa) Valley to the height of the 

 col north of Swains. Overflowing by the Swains-Canaseraga channel into the 

 Dansville Lake, the water ultimatelj' escajjed b}' the Poags Hole col, past the sites 

 of Burns and Hornellsville, to the Susquehanna. 



INNER BORDER PHENOMENA. 



Fi'om the western terminus, near Euclid, Ohio, eastward to the vicinitv 

 of Dunkirk, N. Y., there is a narrow plain lying between this morainic 

 system and Lake Erie. It slopes rapidly from the base of the escarpment, 

 or from the inner border of the morainic system, toward the lake. The 

 greater part of it has been under lake water and well-defined beaches, 

 descriptions of which appear in Chapters XV and XVI, mark the different 

 levels which the lake water has held. 



Over much of this lake plain rock is within a few feet of the sm-face, 

 but there are filled A^alleys crossing the plain in which the drift is very 

 thick. Their courses are in some cases entirely concealed, and generally 

 are rendered quite obscure by the di-ift filling. The bluff of the lake often 

 shows places where valleys come in whose courses across the lake plain are 

 entirely concealed. 



The lake and stream blufPs and the well borings show the drift to be 

 largely till. The coarse pebbles are scarcely so numerous as in the moraine 

 and in places are rare, but, as a rule, this till differs little from the clayey 

 till which covers the plains to the west of Lake Erie. In the intervals 

 between the beaches there is a surprisingly small amount of sand or other 

 wave-washed material, till being usually found within a few inches or at 

 most but a few feet of the surface. The material covering the rock is there- 

 fore largely glacial. 



Upon passing eastward from Dunkirk the Gowanda moraine soon 

 appears and lies within a few miles north of this morainic system from that 



'Glacial lakes of western New York, by H. L. Fairchild: Bull. Geol. See. America, Vol. VI, 

 1895, pp. 358-359. Also Glacial Gen, see lakes: ibid, Vol. VII, 1896, pp. 438-440, pis. 19 and 20. 

 -Ibid., p. 439. 



