90 NEW YORK STATE MUSEUM 



Vcatch of the (joolo^ical Survey and willi them found feldspatbic 

 pebbles, which would in my opinion place the deposit within the 

 Pleistocene series of Lon^ Island. Messi-s Fuller^ and Veatcli^ 

 now repaid the deposit as an exposure of the Manhasset series, 

 presumably pre-Wisconsin, and 1 see no reason at present for not 

 accepting their conclusion. The deposit is necessarily mentioned 

 here on account of its supposed bearing on the marine limit at the 

 mouth of the Hudson. These recent investigations show, it seems 

 to me, that the Far Kockaway gravels even if deposited beneath 

 sea level long antedate the retreat of the Wisconsin ice sheet. 



INTRAGLACIAL EVIDENCE OF WATER LEVELS 



The following notes on particular localities by no means give a 

 complete diagnosis of the retreatal stages of the Wisconsin ice 

 sheet. In none of the cases have the ice margins been traced away 

 from the floor of the Hudson valle3' to the higher levels of 

 morainal accumulation and marginal drainage which undoubtedly 

 can be traced when detailed mapping is undertaken. The account 

 Legins with the outermost moraine on western Long Island and 

 on Staten Island. 



Terminal moraine and out wash plains. The terminal moraine 

 on western Long Island is confronted on the south by a gently 

 sloping creased jjlain of gravel and sand sheeting over older 

 glacial gravels and deposits of Cretaceous age. The surface of 

 this plain is apparently in the state in which it was left when the 

 ice retreated from the crest of the moraine on its northern limits. 

 Its southern margin, now below sea level, exhibits along the shore 

 line unmistaka.l)le signs of recent subsidence. Thus at Babylon, 

 dredging in the drowned outer portion of one of the creases 

 brought up abundant land vegetation from a depth of 10 feet of 

 water. That the material was not transported and deposited was 

 shown by the growth of roots in the peaty layer which formed a 

 part of the mass. Similar facts have long been well known. 



I'orl \\'(fsliin(/l(>n and Collcf/c Point dcllasS' At Tort Wash- 

 ington on Long Island north of the terminal moraine is a well 



'Fuller, M. L. Resurvey of Lonff Island. Science. 



'Voatrh, A. 0. Diversity of tlie Glacial I*eriod on Long Island. Jour. 

 Geol. 100;j. 11 :702-7G. 

 •See N. Y. State Mus. P.ul. 48. 1001. p.653-59. 



