390 



M. L. FULLER — GEOLOGY OF FISHERS ISLAND 



Following the deposition of this series of deposits, with its somewhat 

 complicated history, there was a long period of erosion, during which all 

 of the older materials were extensively eroded, both by marine and 

 stream erosion, before the Wisconsin ice invaded the region. From the 

 extent of this erosion it seems probable that the interval was an exceed- 

 ingly long one, being many times as long as the post-Wisconsin time. 

 This is what would naturally be expected if the period included the 

 Sangamon, Iowan, and Peorian stages of the Mississippi valley, and the 

 correlation with these stages fits in well with the known shortness of the 

 Peorian period in the Mississippi valley, which can not form, judging 

 from the amount of erosion, but a small part of the interval between 

 the Wisconsin and the next preceding invasion in the Fishers Island 

 region. 



DISTRIBUTION OF PRE-WISCONSIN FORMATIONS REPRESENTED ON FISHERS 



ISLAND 



Long island. 

 Gardiner island. 

 Plum island. 

 Fishers island. 



MONTAUK DRIFT 



Block island. 

 Elizabeth islands. 

 Nantucket. 

 Barnstable. 



Cape Cod. 



Indian hill (Plymouth). 



Scituate. 



Boston and vicinity. 



Long island. 

 Gardiner island. 

 Plum island. 

 Fishers island. 



Long island. 

 Gardiner island. 

 Plum island. 



HEROD GRAVEL 



Block island. 

 Marthas Vineyard. 

 Nantucket. 



JACOB SAND 



Fishers island. 

 Block island. 

 Marthas Vineyard. 



Truro. 



Scituate. 



Boston and vicinity. 



Nantucket. 



Cape Cod. 



Boston and vicinity (?). 



GARDINER CLAY 



Long island. 

 Gardiner island. 

 Plum island. 

 Fishers island. 



Block island. 

 Elizabeth islands. 

 Marthas Vineyard. 

 Nantucket (below sea). 



Truro. 



Barnstable. 



Indian hill (Plymouth). 



Boston harbor (?). 



Long island. 

 Gardiner island. 

 Fishers island \ (below 

 Plum island ' sea). 



Block island. 

 Marthas Vineyard. 

 Barnstable (in well). 



Indian hill (Plymouth). 

 Truro. 



