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N E W YORK STATE MUSEUM 



Hudson gorge. At various places near Crugers glacial boulders 

 repose on the clays and frequently in positions where it is im- 

 possible to suppose that they have slidden down from the slopes 

 which overlook the clay deposits. This distribution of boulders 

 is quite in accord with the evidence found on the west side of the 

 river which points to the overriding of certain clays in this part 

 of the Hudson valley by the ice at least in those stages of its 

 retreat which are marked by moraines and frontal washed deposits 

 in the vicinity of Haverstraw and Croton point. It is quite possi- 

 ble that each one of these frontal moraines and attendant out- 

 washed deposits marked a slight advance of the ice remnant fol- 

 lowing a retreat somewhat farther up the river, and the mere 

 overrunning of clays in this manner by the ice itself and the 

 sheeting over them of gravels and sands contemporaneous with 

 the retreating ice as a whole does not of itself demand that these 

 clays be placed anterior to this last ice epoch. But the difference 

 in the geologic position of these clays and those which still form 

 broad plains about Albany and as far down the river as Kingston 

 is sufficient to demonstrate that the clays in the Hudson valley 

 south of the Highlands belong to an earlier stage in the melting of 

 the great glacier than those from Kingston to Albany. In other 

 words, the clays in the lower Hudson were laid down before the 

 final disappearance of the glacier from this part of the valley ; 

 those south of the Mohawk from Albany down to Kingston are 

 later than the disappearance of the ice from the region which they 

 occupy. 



There is thus no continuous deposit of glacial clays in the Hud- 

 son valley precisely equivalent in age to the marine beds of the 

 Champlain area on the north. 



Terraces about Peekskill bay. Well defined terraces of glacial 

 gravels and sands occur in the vicinity of Peekskill bay at the 

 southern edge of the Highlands; at Tomkins Cove and Jones 

 Point on the west shore, and in Peekskill and Peekskill creek 

 on the east shore. These deposits will now be briefly described 

 in the order named. 



Terrace at Tomkins Cove. The topographic map shows a nar- 

 row terrace developed on the side of the valley at Tomkins Gove. 

 This terrace is delimited by the 120 and 140 foot contour lines 

 and agrees very closely in level with the preglacial or inter- 



