No. 30.] STILL RIVER. 3! 



of the headwaters of the Still by a small tributary of the Housa- 

 tonic. 



IV. The Housatonic has always held its present southeasterly 

 course, but the Still has developed from the beginning as a sub- 

 sequent stream in the direction in which it now flows. 



The first hypothesis, that the Still is the ancient channel of 

 the Housatonic, has been advocated by Professor Hobbs, who 

 has stated : 



" That the valley of the Still was formerly occupied by a large stream 

 is probable from its wide valley area. . . The former discharge of the 

 waters of the Housatonic through the Still into the Croton system, on 

 the one hand, or into the Saugatuck on the other, would require the 

 assumption of extremely slight changes only in the rock channels which 

 now connect them. . . To turn the river (the Housatonic) from its 

 course along the limestone valley some obstruction or differential uplift 

 within the river basin may have been responsible. The former seems 

 to be the more probable explanation in view of the large accumulations 

 of drift material in the area south and west of Bethel and Danbury. 



"The structural valleys believed to be present in the crystalline rocks 

 of the uplands due to post-Newark deformation may well have directed 

 the course of the Housatonic after it had once deserted the limestone 

 . . The deep gorge of the Housatonic through which the river enters 

 the uplands not only crosses the first high ridge of gneiss in the rec- 

 tilinear direction of one of the fault series, but its precipitous walls 

 show the presence of minor planes of dislocation, along which the 

 bottom of the valley appears to have been depressed." 1 



The hypothesis proposed by Professor Hobbs and also the 

 second and third hypotheses here given involve the supposition of 

 reversal of drainage, and their validity rests on the probability 

 that the stream now occuying Still River valley formerly flowed 

 southward. The first and second hypotheses will be considered 

 in the following section. 



EVIDENCE TO BE EXPECTED IF STILL RIVER HAS BEEN 



REVERSED 



If Still River occupies the valley of a reversed stream, the fol- 

 lowing physiographic features should be expected : 



i. A valley with a continuous width corresponding to the 

 size of the ancient stream, or a valley comparatively narrow at 

 the north and broadening toward the south. 



1 Hobbs, W. H., Still rivers of western Connecticut: Bull. Geol. Soc. Am., vol. 

 13, pp. 17-26, 1901. 



