78 J. D. Dana on the origin of some of the' 



valley of West Creek appears to have been dissevered from the Bea- 

 ver Pond basin by the same means ; having no river (p. 52) to per- 

 form the office of sweeper, it would have been unable to resist the 

 encroaching sands. 



But while the Beaver Pond depression was thus closed in the direc- 

 tion of West Creek, a tidal communication appears to have been kept 

 oj)en between it and the deep parts of the bay, through the wide val- 

 ley-like depressions near Webster and Munson streets, and thence 

 through East Creek. The gently slojjing sides of the East Creek 

 valley along the course of Chapel and Elm streets below Temple, as 

 well as near Webster and Munson streets, and other facts ah'eady 

 mentioned (p. 54) correspond with the view, as just stated, that this 

 channel was originally a depression in the sandy bottom made by the 

 sweep of the tides. Accepting these views, the channels of East and 

 West Creeks, which diverge at the bay, make together the circuit of 

 the original New Haven square, and converge toward the south- 

 ern extremity of the Beaver Pond depression, were both, though at 

 different times, outlets of this great central basin. 



The valley of Pine-Marsh Creek was another of the deeper glacier ex- 

 cavations, as already explained ; and one too deep to be filled with the 

 droppings of the glacier. This is proved by the remarkable breadth 

 of the valley, and the fact that it is bordered by a steep terrace-slope, 

 although no large stream but that made by the melting of the glacier 

 ever flowed through it. There are deep holes or basins in the plain along 

 its borders which may be explained in the same way as those adjoin- 

 ing the Beaver Pond depression ; that is, they are spots that were un- 

 filled by the sand and gravel of the glacier, because of their dejjth. 



The Quinnipiac valley was far the largest and deepest of the deep 

 basins of the New Haven bay ; for while in one part a mile in width, 

 the terraces on its eastern and western sides are very narrow. More- 

 over they are mostly below the usual height ; and in some places so 

 poorly defined as to be apparently altogether wanting. But to the 

 south, between the basin and the bay, there is a great development of 

 the drift or terrace formation, indicating that over this wide area the 

 material was dropped by the glacier in shallow water. Red sand- 

 stone, the basement rock, outcrops from beneath the sands of the for- 

 mation south of East Rock and in Fair Haven, opposite borders of 

 the plain. The fact that the tidal flow in the bay during the Cham- 

 plain era was not over this area but either side of it (along Mill Riv- 

 er and the Quinnipiac channel), is other proof that the region was 

 originally shallow; for the course of the tidal wave is along the deep- 

 er parts of a bay. 



