GEOLOGY OF THE LONG LAKE QUADRANGLE 499 



in a few protected situations all previously weathered rock was 

 Avorn away, and the present day surfaces are of rock which is fresh 

 except for the slight amount of postglacial weathering. The ice 

 was thickest over the valleys, whose sides were notably smoothed 

 and whose bottoms may have been deepened, though no demon- 

 strative evidence of this has been noted. That the valleys deflected 

 the direction of the ice movement in its basal portions to parallelism 

 with their trend, has already been shown. 



The pronounced topographic effects produced in lofty moun- 

 tains by great ice streams, as many believe, are not to be seen in 

 the region, unless to a very trifling extent. There has been some 

 local sapping of cliffs by bergschrund action, and some tendency 

 to the production of amphitheaters and cirques on the higher 

 ridges. Seward pond, midway on the east margin of the quad- 

 rangle, seems a small cirque pond, but is the only sample of the 

 kind within the quadrangle. There are however a dozen of the 

 type in the more lofty and hilly Santanoni quadrangle next east. 

 The two amphitheaters on the south face of Stony Creek mountain 

 seem due to the same sort of plucking action though no basin was 

 dug out by the ice at the foot of the slope [pi. ii]. Some of the 

 lower level ponds may occupy rock basins dug out by the ice, 

 though there is no evidence at hand that this is the case. In the case 

 of the larger lakes it is quite possible that the ice may have done 

 some excavation on their beds. Long lake trends with the ice 

 motion and may be a rock basin dug out by the ice. But it seems 

 equally well accounted for On the supposition that its drainage 

 went out to the east in preglacial times, and that drift filling in 

 the valley east of Long lake blocked the channel and sent the water 

 over the preglacial col at Raquette falls. Certainly the greater 

 number of the ponds or the quadrangle, both large and small, 

 occupy hollows in the moraine or overwash sand plain surfaces, 

 or else drift-blocked hollows in the partly drift-filled preglacial 

 valleys. The amount of drift deposited in the valleys is consider- 

 able; not so much but that frequent rock knobs protrude above 

 it, but sufficient to everywhere hide the rock floor, and sufficiently 

 variable in amount to give rise to many ponds. 



Drainage modifications. The entire area of the Long Lake 

 quadrangle drains into the Raquette riA^er, except for a small district 

 in the northeast corner, draining into the Saranac, and a somewhat 

 larger one on the southeast, which sends its water to the Hudson. 



