l6 NEW YORK STATE MUSEUM 



It seems warrantable to interpret these features as due to accumu- 

 lations of glacial debris along the margin of the ice-front and indi- 

 cating a pause in the recession of the ice sheet. It is certain that a 

 thick mass of materials was thrown down west of High Mills, ob- 

 structing drainage and giving rise to a glacial lake (Alplaus lake) 

 described below. This obstructing mass was in continuity in east- 

 west direction with the group of hills possessing the features of 

 kames, just described. The facts seem to warrant the view that a 

 recessional moraine was formed extending from near Ballston Lake 

 station westward beyond High Mills. The surface features of this 

 moraine are still evident in its eastern portion ; the western portion 

 is evidenced chiefly by the sand and gravel materials and their 

 arrangement. 



To avoid multiplying distinctions in mapping, I have included the 

 Burnt Hills locality within the area designated " glacial till more or 

 less covered and mingled with . . . glacio-fluviatile deposits . . ." 



KAMES 



A notable group of hills answering to the description of kames 

 occurs in the township of Clifton Park about one mile southeast of 

 Groom Corners. The topographic forms which have been termed 

 mound-and-basin or knob and kettle, are characteristically exhib- 

 ited. The largest of the kettles is designated by depression contours 

 on the topographic sheet. A relief of 60 feet between the bottom 

 of the kettle and the top of the hill immediately to the south is indi- 

 cated by the contour lines. 



All of the hills have rounded or moundlike outlines but with 

 much irregularity of shapes. Some of them are elongated and with 

 somewhat steep slopes. The longest of the hills trends in a north- 

 east-southwest direction. It may represent a deposit made by a 

 subglacial stream or stream emerging from the edge of the glacier. 



The materials of composition of the hills are fairly distinctive in 

 character. There is a predominance of gravel, consisting of small 

 and large pebbles and cobbles together with course sand and frag- 

 ment of the local bedrock. No exposures were found sufficient to 

 determine the arrangement of the materials. 



There is a ridgelike accumulation of gravel just west of the large 

 kettle which suggests heaping effects against an ice-block. 



Th6 Lake Albany deposits. A large part of the area of the Schen- 

 ectady sheet is covered with deposits of clays and sands which are 

 continuous with similar deposits lying to the east and which have 

 been interpreted by Woodworth and others as deposits of delta 

 origin made in the extensive body of glacial waters known as Lake 



