112 I). F. Lincoln — Glacial Erosion of New York. 



The smaller upland creeks above named, lying nearly 1000 feet 

 higher than the Seneca bottom, and distant only 4 or 5 miles, 

 without obstructing elevations of ground, must inevitably 

 have become its tributaries. But not the first step seems to 

 have been taken towards this end. The upland systems were 

 uninfluenced, during their formation, by such an attraction ; 

 hence we may infer its non-existence. 



o. Probably the most important argument in this direction 

 is drawn from the absence of side valleys along Seneca and 

 Cayuga Lakes. In this respect, the lake-scenery presents a 

 remarkable contrast to that of the valleys lying beyond the 

 line of moraine, which are entirely typical in this respect. 

 The contrast is observed immediately on crossing the moraine, 

 e. g. to the south of Havana ; still better, along Cayuta Creek. 

 While the latter valleys are notched down to the flood-plain 

 level, every mile or two, the lake-side for stretches of 10-15 

 miles seems like an artificially smoothed garden-slope. 



Professor Chamberlin noticing this, suggests as a probable 

 view, that at least one-half of the depth of the old side-valleys 

 has been lost through the shearing action of the glacier upon 

 the projecting bluffs. The remainder of the effect is due to 

 filling with drift. This is exactly in the direction of the 

 present line of thought. But it seems necessary, in view of 

 certain conditions, to carry this observer's views to a somewhat 

 more radical conclusion. These conditions ave the following: 



The upper twenty miles of Seneca Lake is bordered by a 

 continuous line of cliff, varying from 20 to 100 feet in height, 

 but presenting only very gradual changes in level. As the 

 coast forms almost a straight line, the inference is clear that no 

 deep incisions exist at that level, or from 500 to 600 feet above 

 the lake-bottom — practically, about half-way up the valley-side, 

 where the side-notches would have made the deepest incisions. 

 These remarks are intended to apply only to such small, but 

 deeply cut notches as would correspond to streams of half-a- 

 dozen miles in length : such, for instance, as may be seen by 

 following the valley ten miles southwards from Watkins. 

 Larger valleys, joining the lake at near the present water-line, 

 may be instanced ; Seneca «Lake has one such at Dresden, 

 which seems to have formed the original outlet of Keuka 

 (Crooked) Lake ; the Post-glacial gorge follows the same route. 

 Cayuga Lake has the valley of Salmon Creek, opening at 

 Ludlowville, near Ithaca, and running some 16 miles midway 

 between Cayuga and Owasco Lakes. The bottoms of these 

 valleys contain a very heavy deposit of drift, but not enough 

 to prevent their forming impressive features of the landscape. 

 Other than these, no important valleys enter the two lakes. 

 The fluctuations in the height of the lake-cliffs suggest that 



