No. 3O.] STILL RIVER. 47 



pass could not, therefore, have served as an outlet for Still River. 

 The valley west of Town Hill is similar in form and origin 

 to Sugar Hollow. The water parting occurs in a swamp, from 

 each end of which a small brook flows. The height of the pass 

 in this valley 590 feet precludes its use as an ancient outlet 

 for Still River. Likewise the valley east of Town Hill affords 

 no evidence of occupation by a southward through-flowing stream. 



THE ANCIENT STILL RIVER 



The conclusion that the Still-Umpog was not reversed by a 

 glacial dam does not preclude the possibility that this valley has 

 been occupied by a south-flowing stream. It is probable that in 

 an early stage in the development of the drainage, the streams 

 of the Danbury region reached Long Island Sound by way of 

 the Still-Umpog-Saugatuck valley. Along this route, as described 

 under the heading " The Still-Saugatuck Divide," is a fairly 

 broad continuous valley at a higher level than the beds of the 

 present rivers. A south-flowing river, as shown in fig. 9, 

 brings all the drainage between Danbury and the Housatonic into 

 normal relations. 



This early relationship of the streams was disturbed by the 

 reversal of the waters of the ancient Still in the natural develop- 

 ment of a subsequent drainage. The Housatonic lowered the 

 northern end of the limestone belt, in the region between New 

 Milford and Stillriver village, faster than the smaller south- 

 flowing stream was able to erode its bed. Eventually, a small 

 tributary of the Housatonic captured the headwaters of the south- 

 flowing river, and by the time the latter had been reversed as far 

 south as the present divide at Umpog Swamp, it is probable that 

 the advantage gained by the more rapid erosion of the Housatonic 

 was offset by the Saugatuck's shorter course to the sea. As a 

 result the divide between Still and Saugatuck Rivers at Umpog 

 Swamp had become practically stationary before the advent of 

 the glacier. 



The complex history of Still River is not fully shown in the 

 stream profile, for the latter is nearly normal, except in the rock 

 basins in the valley of the Umpog. This is due to the fact that 

 changes in the course of the Still, caused by the development of 



