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NEW YORK STATE MUSEUM 



traced, the evidence on the east of the valley in the form of 

 lateral moraine terraces shows that a long tongue of ice lay 



Fig. 17 Sketch map designed to show manner in which the glacier retreated in the 

 Hudson valley. A, ice front at Tappan X. Y.; B, protrusion of glacier through the High- 

 lands to Croton point; C, a later stage in the same; D, same stage as C when the ice still 

 filled much of the lowland north and west of the Highlands; E. the Xewburg stage. The 

 western limits of the ice at the Xewburg stage are conjectural. Definite margins of the 

 ice on the eastern side are shown by ice contacts at F, F, F. Vertical ruling in areas over 

 1000 ft in elevation 



over the gorge and for some miles east of the present river hold- 

 ing up the drainage of the side streams for a time, giving a 

 more or less definite belt of deposits traceable northward as 



