298 D. F. Lincoln — Glaciation in the 



rises for 1^ miles eastward, reaching a height of 150 (?) 

 feet, and forming a broad-backed N-S ridge of Hamilton shale 

 covered with a couple of feet of drift. A third ridge 250 feet 

 high, at a similar inteiwal to the S.E., slopes very evenly to the 

 lake (2^ miles distant) over rock covered with a very few feet 

 of drift ; in this case no cliff is formed, the rock not quite reach- 

 ing the lake. The axis of this hill points N. 20°-30° W. 

 On Cayuga lake, south of Aurora, there is a hill 300 feet in 

 height, forming a cliff at the lake-side, two miles long and one 

 mile across, with its long axis directed N.W.-S.E., composed 

 of Hamilton shale. The top of this hill, for the length of a 

 mile, forms a plateau. A smaller hill of Marcellus shale lies 4 

 miles to the north of this. 



In the present state of the question it is admissible to sup- 

 pose that these hills may be remnants of preglacial hills of 

 bolder outline. The fact that they lie parallel to the lake need 

 not militate against this view, since the old valleys of the 

 region — farther south than the hills described — unite with the 

 lakes and with each other at very acute angles. 



The hills may constitute a very insignificant remnant of old 

 hills ; or may even have been carved out de novo from rock 

 which occupied levels below the roots of their predecessors. 

 In other words, the corrasion at the latitudes of Geneva and 

 Auburn may have removed one hundred or several hundred 

 feet. Definite evidence limiting these estimates is not before 

 me. Apart, however, from the numerical estimate, it is interest- 

 ing to note the parallelism between the axes of these hills and 

 those of the drumlins which are found close by. Their mate- 

 rial, a soft shale, yields readily to force applied horizontally, 

 and it is not beyond the province of legitimate speculation to 

 suggest that their forms may have been carved at the same 

 time and in similar circumstances with the drumlins. Their 

 bluffer northern sides, and their exceedingly gentle southern 

 slopes, add much to the likeness. 



A system of small valleys for local drainage, opening lake- 

 ward, doubtless existed before glaciation. We can point to no 

 surviving representatives of these valleys at the lake level unless 

 the slight depressions in the cliff line be taken as such. These 

 descending curves run but a short distance below the lake level, 

 and represent but slight inward bends of the rock-shore. If the 

 lake were drained, the present mouths of the brooks flowing in 

 these hollows would be a mile from the main stream which 

 presumably occupied the axis of the valley. In going this 

 mile they would fall from 300 to 600 feet. Such streams 

 must have cut deep and wide gorges extending far inland. 

 How deep some of these would have been at parts of the lake 

 where the shores are bolder, may be estimated by considering 



