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NEW YORK STATE MUSEUM 



that smaller stream. Turned aside, probably by depth, of drift, 

 the river encounters the ponderous rock ridge at the High falls, 

 in which it has cut a very considerable gorge, which appears 

 wholly postglacial. The position of the preglacial channel here- 

 about has not been ascertained, a fairly continuous line of rock 

 outcrops occurring to the northward and many appearing to the 

 south of the present channel. 



Beyond the High falls the valley is again broad and filled with 

 drift. At Cadyville the river is once more out of its old channel, 

 and has cut quite a gorge in the Potsdam sandstone at that point. 

 From Cadyville to the mouth of the river at Plattsburg the fall 

 is 400 feet and the distance 10 miles, giving a rate double the 

 average fall of the stream, yet the bottom of the drift filling is 

 nowhere reached save at the pulp mill, 2 miles above Plattsburg, 

 where a long but not deep cut through the Beekmantown lime- 

 stones has been made, and at Plattsburg itself. 



Two thirds of the 1400 foot fall of the Saranac is made in the 

 lower one third of its course, giving a highly convex profile. The 

 Ausable follows its old valley more closely, crosses the 1000 

 foot contour much farther from its mouth and has a profile not 

 notably convex. The northwesterly streams all have convex 

 profiles also. 



The Eaquette drainage shows some interesting and puzzling 

 features. The reach from Raquette falls to Piercefield is much the 

 longest shown by any Adirondack stream. In all this distance 

 the valley is wide and mature, the river flows in great loops 

 which reach the rock walls but seldom, cut-off oxbows are ex- 

 ceedingly common, and the valley floor is mainly one great swamp. 

 The valley narrows to Raquette falls, where there is a fall of 70 

 to 80 feet in a gorge % of a mile long, in which the water is rapid 

 throughout, but with two principal falls [pi. 18]. There is an 

 impassable rock barrier here, with no opportunity for a buried 

 channel, so that there could have been no preglacial drainage 

 line; rather, there was here a col between small streams flowing 

 both ways from the obstruction. Above Raquette falls the valley 

 widens southward, as it should on this supposition. It was 

 occupied by a small preglacial, south flowing stream, which either 



