equent 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 a subsequent
drainage through differential erosion, were made so long ago that
evidence of them has been largely destroyed.

The foregoing conclusion practically eliminates hypothesis IV--that
the Still developed from the beginning as a subsequent stream in the
direction in which it now flows. This hypothesis holds good only for
the short portion of the lower course of the present river, that is,
the part representing the short tributary of the Housatonic which
captured and reversed the original Still.

DEPARTURES OF STILL RIVER FROM ITS PREGLACIAL CHANNEL

Between Danbury and Beaver Brook Mountain the Still departs widely
from its former channel, as shown in fig. 6. At the foot of Liberty
Street in Danbury the river makes a sharp turn to the southeast, flows
through a flat plain, and for some distance follows the limestone
valley of the Umpog, meeting the latter stream in a swampy meadow. It
then cuts across the western end of Shelter Rock in a gorge-like
valley not over 200 feet wide. Outcrops of a gneissoid schist on the
valley sides and rapids in the stream bear witness to the youthfulness
of this portion of the river channel.

An open valley which extends from the foot of Liberty Street in a
northeasterly direction (the railroad follows it) marks the former
course of Still River, but after the stream was forced out of this
course and superimposed across the end of Shelter Rock by the
accumulation of drift in the central and northern parts of the valley,
it was unable to regain i