2:V2 



NEW YORK STATE MUSEUM 



POSSIBLE OBJECTIONS TO THE ELEVATION THEORY 



The view presented in this report tliat the land was for a part 

 of the time during Ihe retreat of the ice and at the time of the 

 maximum submergence on the north several hundred feet higher 

 than now at the mouth of the Hudson is. 1 am aware, in distinct 

 opposition to the views held by some geologists and it seems 

 necessary in this connection to meet the objections which may be 

 raised so far as is permissible by the evidence now at hand. It 

 should be borne in mind how^ever that the time since the ice 

 began to retreat is relatively long when compared with the time 

 taken for such changes of level as are admitted by all in the St 

 Lawrence district and that it may be that what at first is regarded 

 as contradictory evidence of elevation and subsidence about the 

 mouth of the Hudson river is but proof of movements which have 

 succeeded each other. 



Early in the field work on Avhich this report is based it seemed 

 to me probable that the land about New York city had not under- 

 gone since the ice began to retreat, a notable change of level 

 either of uplift or depression and after examining the typical 

 marine deposits and shore lines of the Champlain district it 

 became evident that no recent marine deposit had been seen by 

 myself or convincingly described by others above the most recent 

 beaches in that southern field. I believe that one who has had 

 the opportunity of studying attentively the Champlain marine 

 district will be compelled to abandon the view of a postglacial 

 submergence within the field of the Wisconsin drift sheet about 

 New York city other than that now in progress. 



The most positive statement which the elevation theory has to 

 meet is the supjiosition of Professor Salisbury,^ that the gravels of 

 the Far Rockaway ridge on Long Island are a marine shallow 

 water dejjosit of a date as late as the ice retreiit, and the statement 

 that they are regarded by him as the local equivalent of his 

 Cape May formation in Southern New Jersey. From a recon- 

 naissance of i!)c area on Long Island I had about the same 



'Salisbury, R. D. in (^.oolojjic Atlas of the United States, New York City 

 Folio, no. 83. 1002. p.l5, 16; also Surficial Geology Sheet of the Brooklyn 

 Quadrangle, where the Far Rockaway deposit is given as "gravel and sand 

 of marine shallow water origin." 



