ICE-SHEET EROSION IN NEW YORK 



61 



Convexity of valley sides. — Cross-sections of the Finger Lakes val- 

 leys (figure 5) show convex valley slopes, not the concave profiles and 

 U shape attributed to ice-worn valleys (see page 28). It would seem 

 unreasonable to claim that the glacier cut hundreds of feet merely at 



Canandaigua valley. 

 I. Section at head of lake. 

 II. Section at Long Point. 



Keuka valley. 

 Section at Grove Spring 



Seneca valley. 

 I. Section 4 miles from head of lake. III. Section at Lodi. 



II. Section 1 mile south of North Hector. IV. Section 4 miles north of Willnrd. 



Cayuga valley. 



I. Section 2 miles from head of lake. II. Section 4 miles north of Trumansburg. 



III. Section at Aurora. 



Ovvasco valley. 



Section at Ensenore, 3% miles 



from head of lake. 



Skaneateles valley. 



Section at Glen Cove, about 4 miles 



from head of lake. 



Figure o.— Generalized Cross-section Profiles of Finger Lakes Valleys, looking north. 

 Plotted from the topographic sheets; the vertical scale G.5 times the horizontal. 



the bottom, and not enough along the sides, in soft shales, to produce 

 concave profiles of the valley walls. 



The profiles beneath the lakes are apparently harmonious with the 

 convex profiles of the exposed walls. Other valleys without lakes show 

 the bottom contours, with some filling. As should be expected, these are 



IX— Bull. Geoi.. Soc. Am., Vol. 16, 1904 



