SOME RIVERS OF CONNECTICUT, Z77 



view of the successive cycles in the physical development of the 

 region. In another part of this article I shall consider these 

 gaps again in connection with their river histories, and shall give 

 additional reasons why I venture to differ from so eminent an 

 authority. 



Length of this cycle. This cycle of erosio~n beginning with 

 the post- Cretaceous uplift was not so long as the preceding cycle. 

 In the earlier one the whole state was reduced to a peneplain; in 

 the later cycle only the soft Triassic sandstones were brought near 

 to baselevel. It probably lasted through Tertiary times, and was 

 brought to a close by a slight uplift. The result of this uplift 

 is well shown in Pennsylvania^ and New Jersey^ It is not well 

 shown in Connecticut, but there seem to be some traces of it in 

 the trenches the rivers have cut below the level of the sandstone 

 peneplain. However, these trenches are so much obscured by 

 drift that a positive statement is not warranted. It may, how- 

 ever, be spoken of provisionally as the post -Tertiary uplift. 

 There may have been later oscillations of small amount, probably 

 were ; here and there are shreds of evidence which point to such 

 oscillations, but only one movement has had an effect upon the 

 topography, which can be recognized. The fjorded condition of 

 all the rivers along the Sound — the Norwalk, Saugatuck, New 

 Haven bay, Niantic and Thames are the best examples — shows 

 that within comparatively recent time there has been a slight sub- 

 sidence of the land. But this movement is not to be compared 

 in amount with those of the earlier cycles. 



The drift. Over all the state in varying thickness lies the 

 glacial drift, either in its typical unmodified development as till, 

 or in its modified form, as river terraces, kames, eskers and sand- 

 plains. It is of importance in this connection only as it has 

 affected the topography of the country and so modified the 

 drainage. Examples of these modifications will be mentioned 

 later. 



Resume. There was first a long cycle of denudation in pre- 



' McGee. Amer. Jour. Sci. 3d ser., vol. xxxv, p. 376. 



-Davis and Wood, Geographic Development of Northern New Jersey, pp.413, 

 414. 



