GLACIAL GEOLOGY OF THE SARATOGA QUADRANGLE 1 3 



movement of the ice in the localities where they occur and at that 

 stage of glacial history when the striae were formed. 



The data given above show a movement of the continental 

 glacier in the region under consideration in the general direction of 

 about 42 ° west of south. This is in accord with the statement of 

 Chamberlin 1 to the effect that the ice moved around the south- 

 eastern border of the Adirondack region and thence westerly in the 

 Mohawk valley. It is also shown, on the evidence of the drumlins, 

 that this was the direction of movement of the ice at the time of its 

 latest general advance (Wisconsin stage). 



The data afford evidence of the influence of local topography on 

 the direction of ice movement. The striae pointing 16 west of 

 south at locality no. i, as well as the direction of the well-defined 

 drumlin about a mile to the north of this locality may indicate that 

 the deeper portion of the mass of ice lying over the Hudson plain 

 was controlled in its direction of movement by the fault scarp. 

 Comparing locality no. 3 with the former, it appears that as soon 

 as the ice pressing against the fault scarp passed this barrier it 

 became deflected to the west, its movement thus merging with that 

 of the general glacier. It is evident, however, that this control of 

 movement by the scarp was not constantly effective, inasmuch as 

 at the same locality (no. i) there are other striae pointing about 

 48 west of south. It is possible that it was only during the waning 

 of the ice sheet, when the mass had thinned or disappeared on the 

 highlands, that the scarp controlled the direction of motion of the 

 persistent ice occupying the Hudson plain. 



The direction of movement of the ice in the central basin, as in- 

 dicated especially by the long axes of the drumlins, trended pro- 

 gressively to the west of south. In this a general parallelism with 

 the line of the base of the slope of the Adirondack spur west of the 

 basin is exhibited. It is inferred that the flow of the deeper por- 

 tion of the mass of ice occupying the central depressed region con- 

 formed to the lay of the slope. 



EROSIVE EFFECTS OF ICE MOVEMENT 



There is evidence of vigorous ice action over the eastern high- 

 lands region, and on its southern slope. Along the road running 

 from Kings Station to Kings there are frequent exposures of knobs 

 and knolls of smoothed rock. In many cases the exposed surface 

 faces northward, or northeastward, indicating that the abrasion is 



1 U. S. Geol. Survey, 3d Ann. Rep't, p. 361-65. 



