No. 30.] GLACIAL DEPOSITS, 55 



the two tracks of the New York and New England railroads con- 

 verge, a cut shows a section of at least 40 feet of boulder clay. 

 Near the river, limestone boulders are common, indicating that 

 the valley to the north was degraded to some extent by the 

 glacier. 



In the valley at Brookfield Junction and on its western side, 

 are thick deposits of clean sand. One mile north of Brookfield 

 Junction, along the western border of the- valley, an esker follows 

 an irregular course for several hundred yards approximately 

 parallel to the river and terminates at its southern end in a group 

 of kames (PL V, A and B). Opposite the point where these 

 accumulations occur, is a terrace-like deposit of till. Between the 

 gorge at Brookfield and the mouth of Still River, swampy areas, 

 flat meadows, and small hills of drift occur. 



In comparison with the Still River lowland, the flat land east 

 of Green Mountain may be called a plateau. The step between 

 the two is made by an east-facing rocky slope, the outline of 

 which has been softened by a lateral moraine separated from the 

 plateau edge by a small ravine. On the lowland below the 

 moraine is a group of kames. Near Lanesville (fig._6), are thick 

 deposits of water-laid material, including a hill of gravel near the 

 river having a large bowl-shaped depression on one side formed 

 by the melting of an ice block. Two and a half miles south of 

 Lanesville on the west side of the lowland, a wooded esker ex- 

 tends for about one-quarter mile parallel to the valley axis and 

 then merges into the rocky hillside. 



LAKES 



The lakes of this region are of two kinds: (i) those due to 

 the damming of river valleys by glacial deposits and (2) rock 

 basins gouged out by the ice. 



Among the lakes which owe their origin to drift accumulations 

 in the valleys are Andrew and Raines' ponds at the head of Still 

 River. These are properly parts of the Croton River system, but 

 Andrew Pond has been held back by the deep filling of boulder 

 clay in the valley. Lake Kanosha, in the same valley, is a shallow 

 lake formed in the drift. The lake south of Spruce Mountain at 

 the head of the Saugatuck seems to be enclosed by drift alone. 



