Topographical Features of the New Haven region. 77 



a stroke is but little, and this is spread widely, (4.) Again, they 

 could not have been formed as sea-beach deposits. They have not 

 the structure of such deposits. Moreover, if the beds of the New 

 Haven plain had been produced by the gradual growth of a beach 

 seaward, the harbor would have also existed somewhere, in narrow 

 areas at least, among the encroaching beaches, and remains of the co- 

 temporaneous mud-flats of the harbor should occur to mark its posi- 

 tion. But no such clay or mud deposits have in fact any where been 

 found, except in the Quinnipiac valley (upon which we remai'k be- 

 yond) ; none along the courses of Mill and West rivers, where we 

 should naturally look for clayey interpolations among the sands, if 

 not thick beds. The work of filling up the bay was evidently too 

 rapidly done for the accumulation of mud or clay from the contribu- 

 tions of rivers. 



3. Filling of depressions with the drift. — The depositions from 

 the glacier filled up the greater part of the New Haven bay nearly or 

 quite to the sea limit, as is shown by the even surface of the plain, 

 the whole having been leveled off by the waters. The rivers, whei'e 

 not too deep to be filled, had currents to sweep out the sand and keep 

 them clear. 



The Beaver Pond depression, the great central basin of the bay, 

 was one of the unfilled channels ; and unfilled, in all probability, be- 

 cause of its depth. The drift was dropped over it as over the rest of 

 the bay ; but its depth saved it from obliteration ; it still remained 

 the open central basin of the bay. Its original communication with 

 the wider outer portion of the bay was probably, as has been shown 

 (p. 53), through the West Creek channel, whose extent, north-and- 

 south course, and approximate conformity in direction and line 

 with the Beaver Pond basin, accord with this view. During the melt- 

 ing of the glacier there would have been an abundant flow of waters 

 from the northward through it ; and these currents, together with the 

 inward setting of the tidal flow, would have made the steep terrace- 

 slopes that form its boundary, and those also of West Creek valley, 

 which resemble in all respects the terrace-slopes along the rivers. 



But while not filled by the depositing drift, the Beaver Pond de- 

 pression appears to have lost mucli in breadth ; for in the surface of 

 the adjoining plain, especially along Crescent street, there are several 

 large isolated basin-like depressions — deep holes, as they are often 

 called, although sometimes 100 yards or more across — which must 

 have been cut off by the depositions made by the glacier. The east 

 and west Goffe street ponds occupy such exscinded depressions. The 



