42 NEW YORK STATE MUSEUM 



erosion resulting in these gorges was the work of the flooded 

 waters of the late glacial and early postglacial times ; but the process 

 has continued during the present epoch and is still in progress. 



With the gradual' deepening of the Aqueduct gorge the Mohawk 

 waters, sweeping in a great half circle, cut into the western edge 

 of the Lake Albany deposits forming the basin near Schenectady. 

 At the same time the waters, as they issued from the gorge, spread- 

 ing in their course, swept away the sands and clays in their path, 

 forming the basin east of Vischer Ferry. In the recent epoch the 

 surfaces of these basins have been overlaid with alluvium. 



The plains left by the subsiding Lake Albany waters were early 

 swept by strong winds which, over extensive areas, lifted the sur- 

 face sands, transporting them mainly eastward. Thus were 

 formed, on the one hand, wind-denuded and leveled tracts and, on 

 the other, the regions marked by hills and ridges of wind-blown 

 sands. 



