Finger-Lake region of New York. 295 



of 90 feet above the lake. The other ridges increase in absolute 

 elevation, but not in size, having an apparent height of 20-50 

 feet above the ascending slope which they cover. At some- 

 what over a mile from the shore they attain a height of 300 

 feet above the surface of the lake, which corresponds with the 

 verge of the higher levels of land. Similar ridges are found 

 for several miles farther west ; sometimes crossing the road 

 at pretty regular intervals of J to -g- mile, with elevations 

 of only a few feet ; at other times forming hills with a rather 

 bold northern descent. 



A distinct termination north and south can generally be 

 traced in the ridges of the Geneva group, although the ordi- 

 nary observer is inclined to overlook the fact. Their general 

 outline, their material, and their tendency to steepness at the 

 •north end, ally them with the drumlins of the northern belt. 

 The long ridge running west from the end of the lake is of 

 typical till, with some large bowlders, overlaid, in part by 

 stratified sandy clay. 



In this locality, the till evidently forms a continuous sheet, 

 of which the ridges are merely a surface irregularity. 



The slope of the sides of the ridges is about from 2° to 10° 

 at Geneva, and their crests are occasionally from 100 to 300 

 feet wide. 



• The direction of the ridges of till as a whole is probably 

 similar to that of the glacial striations, that is, convergent to a 

 northerly point. At Clyde and Lyons (on the central axis of 

 the region) they run a degree or two west of north. Near 

 Cayuga, about JN. 8° W. ; and still further east, about 20° west 

 of north. 



The till at Geneva is a firm " hard-pan," containing a great 

 number of subangular striated stones of all sizes up to three 

 feet in length. The greater part of the stones are from the 

 Corniferous limestone, which is exposed just north of the vil- 

 lage. Of those representing more northern formations, many 

 are water-rolled. The limestone fragments give a bluish tint 

 to the otherwise reddish brown mass. 



About three feet of the upper part of this till appears thor- 

 oughly oxidized and leached. This portion is a red clay, dis- 

 tinctly contrasted with the gray-blue till, and rather well 

 demarcated. It is of a deep shade, unstratified, very tenacious, 

 nearly free from sand ; at times flaky, at times tending to split 

 when dry into rectangular forms. It cuts with a slight gritti- 

 ness ; the surface is dotted with occasional specks of material 

 not fully decomposed, which may represent some of the 

 myriads of little bits of limestone found in the till. The 

 stones are few, chiefly snch as resist oxidation (quartzites) ; 

 these correspond in appearance and amount with a simliar 



Am. Jour. Sci.— Third Series, Vol. XLIV, No. 262.— October, 1892. 



20 



