Finger-Lake region of New York. 297 



long. The field-stones in this region split, losing their like- 

 ness to till-stones. Hence the " flat gravel," characteristic of 

 the soil of the hilly districts. 



The deltas of the lake sides are among the most conspicuous 

 accumulations of drift material. Rising at intervals along the 

 sides of the lakes and the southern continuations of their val- 

 leys, they attain by a series of steps the height of (?) 400 feet 

 above the lakes. Their strata contain many stones which still 

 show half obliterated glacial strise. 



The remainder of this paper will be devoted to certain points 

 of preglacial topography and drainage, and the associated 

 questions of amount of glacial corrasion, and bulk of drift- 

 deposit. The northern zone, except as specially designated, 

 will be omitted from consideration. 



The deposits of the terminal moraine are very heavy ; for a 

 description of this feature the reader is referred to the paper 

 on this subject by Thomas C. Chamberlin. 



From considerable examination of the country included 

 between the four larger lakes, the writer has been led to set a 

 moderate estimate upon the amount of drift, and a very high 

 estimate upon the amount of erosion in certain parts. 



The lakes are to a great extent bordered by vertical cliffs of 

 rock, with little or no beach at their foot. Owing to the 

 greater prevalence of westerly winds the cliffs are best developed 

 on the east side. In the case of Cayuga Lake this natural facil- 

 ity is aided by the presence of a railroad at the water's edge, 

 for which in many places the cliffs have had to be cut. From 

 Aurora southward for nearly 20 miles the top of the cliff is 

 visible most of the way, undulating in very moderate curves, 

 occasionally rising 50 feet or more, and at several points sink- 

 ing below the level of the lake for short distances. In the 

 latter case the rock is exposed in brooks a few rods inland. 

 Till overlies this rock, varying in thickness from 2 to 40 feet. 

 The till deposits along the east shore of Seneca lake are appar- 

 ently not much in excess of the above. 



It is probable that the rock-sections thus displayed correctly 

 represent the general surface of the region as it would appear 

 if the drift were removed. In some tracts, at all events, this 

 is demonstrably the case. In the northern reaches of the lakes, 

 hills of rock with a very flat curve correspond with these cliffs. 

 A few examples may be worth describing. At the foot of 

 Seneca Lake on the east side there is a line of cliff (Marcellu6 

 shale), which rises gradually to a height of .25-30 feet and ex- 

 tends more than a mile. A hill-side rises directly from the 

 brow of this cliff to the height of about 90 feet ; mainly rock 

 with 2-20 feet of till. Three miles to the southward is another 

 long shore-cliff of rather greater height, the land behind which 



