CAPE COD GEOLOGY 



195 



local material than the morainal gravel. Much of the outwash gravel was prob- 

 ably derived from the earlier Pleistocene deposits of this region from those of 

 the region just to the north. Most of the after outwash probably came from 

 the Cape Cod Bay lobe, for all branches of Tisbury Great Pond and the ponds 

 east of it head toward this lobe and not toward the Buzzards Bay lobe, although 

 that was much nearer. The main streams, at least near the end of Wisconsin 

 time, came from the northeast, and as they were the means of transportation 

 the material doubtless came from the same direction. 



The Manhasset formation probably underlies most of the outwash, and no 

 doubt early Pleistocene deposits as well as the Cretaceous beds underlie in 

 places both the Manhasset and the outwash. The surface of the Manhasset 

 must have been considerably eroded during the Vineyard interval, and probably 

 the great volume of water issuing from the Wisconsin ice further eroded and 

 re-deposited parts of that series. Thus the outwash deposits must rest uncon- 

 formably on the older beds, although the form of the general surface of those 

 beds may not have been much different from that of the surface of the present 

 outwash. 



