GOWANDA MOEAINE. 675 



it contains less clay and is tliickly set with small fragments of the shaly 

 sandstone of that region. 



In the valleys of Eighteenmile and Cazenovia creeks there are heavy 

 deposits of silt and fine sand Avhich were apparently laid down in water. 

 These ai-e capped by a few feet of stony material, some of which is assorted. 

 The knolls and ridges which constitute the moraine proper carry consid- 

 erable gravelly material. 



In railway cuttings north of Growanda beds of graA^el are exposed 

 beneath the till, the till being in places only 6 to 8 feet thick. The gravel 

 shows discordant stratification, some beds being horizontal and others 

 having a sharp inclination. • The gravel is only a local phase, for it passes 

 horizontally into unmodified till within a space of a few rods. 



A bank of till 100 feet in height is exposed on the west side of Catta- 

 raugus Creek about a mile west of Growanda. It is of blue color and 

 clayey, j^et much of it is thickly set with stones, there being only a small 

 part in which pebbleless clay appears. The coarse fragments are largely 

 • of local shaly sandstone, but limestone pebbles are not rare, and there are 

 not a few Canadian crystallines. This till was probably deposited while 

 the ice sheet stood farther south than the Gowanda moraine, and may, 

 therefore, not form a part of that moraine. It is capped by a few feet of 

 gravel which was deposited as a delta in connection with the Belmore 

 beach, its altitude being about the same as that of the beach. 



The Growanda moraine carries a remarkably large number of surface 

 bowlders. These serve to indicate its limits in places where the topographic 

 expression is weak. They are largely granitic rocks, though many other 

 Canadian crystallines are represented. The bowlders do not seem to be so 

 numerous beneath the surface; at least there are but few exposed in the 

 banks or bluffs of the streams and they are seldom struck in the excavation 

 of wells. 



OUTER BORDER DRAINAGE. 



The position of the ice margin at the time this moraine was forming 

 was very unfavorable for such a southward discharge of glacial waters as 

 took place in connection with the deposition of earlier moraines. South- 

 ward discharge could have been accomplished only by a ponding of waters 

 south of the ice margin to sutficient height to raise the water surface to the 

 level of the passes across the divide. This would demand lakes about 400 



