1 8 NEW YORK STATE MUSEUM 



permit of it. In fact no very distinctly cut shore lines are to be found on 

 the drift about New York even at an altitude corresponding to that of the 

 Hudson estuary deposits. Apart from the still-water deposits the 8o-foot 

 postglacial depression about New York can only be traced by change of 

 surface slope and material at this level. Even these two varieties of evidence 

 are not always coexistent. 



Beach phenomena have scarcely been recognized on territory of 

 New England which was 'almost certainly submerged during the 

 removal of the ice sheet. Professor Shaler explained the lack of 

 beaches on Martha's Vineyard and Nantucket by the too rapid lift- 

 ing of the shores.^ 



To the above sound and quite sufficient argument something may 

 be added. On the open sea shores of Long Island and Staten 

 Island there was an inhibiting factor besides the rising of the land, 

 namely, the tidal fluctuations of level. A very little change in the 

 water level may effect large difference in the force and direction of 

 shore currents and effectively change the plane of bar construction 

 or of beach erosion. 



However, there is an erosion cliff' on the face of Staten island 

 and on the west end of Long Island as far as Lake Surprise, 6 

 miles beyond Jamaica. This has been recognized as a possible 

 beach, and Fuller has given a clear description of it as " the great 

 inland cliff of western Long Island" (54, page 54). He clearly 

 proves the origin of the cliff as by marine erosion, but makes it 

 earlier than the end of the AVisconsin epoch. But the altitude and 

 slant of this and the Staten Island cliff agree with our map, plate 9. 



The above discussion relates particularly to erosional .shore fea- 

 tures. Constructional features, bars and embankments are more 

 common and under favorable conditions more readily produced by 

 waves. It might properly be expected that bars and beach ridges 

 would appear, especially on the broad sand plains of the south side 

 of Long Island. The lack of such phenomena has been a strong 

 point for these who assert nonsubmergence. 



Students of ancient shore lines find gaps along beaches that are 

 commonly strong. It requires considerable time for wave and 

 shore currents, even at steady levels, to bridge unfavorable 

 stretches. On shores as strong as those of the glacial Lake Warren 

 and Lake Iroquois localities are found with only smooth, wave- 

 washed slopes comparable to the low surfaces of Long Island and 

 Staten Island. Followino- the removal of the sheet the land rose 



^ Geology of Martha's Vineyard. Seventh Annual Rep't, U." S. Geol. Sur- 

 vey, 1888, p. 321. 



