8 NEW YORK STATE MUSEUM 



southeast corner, is well brought out by the contours. It is 

 interesting to note the way in which the feeders of Niagara brook 

 all come in from the western side. Escarpments hem in the lower 

 Ausable lake on both sides. They also do the same but in less 

 pronounced fashion for the Cascade lakes. The pass on the north- 

 west side of Pitchoff mountain is precipitous on both sides and is 

 impressive for this reason. All these cliffs probably are on the 

 lines of old faults and all have doubtless been freshened up by 

 the plucking action of the continental ice sheet. 



Drainage. The mountains of the quadrangle constitute a divide 

 between the Hudson and the Lake Champlain systems of drainage. 

 Niagara brook and the outlet of Elk lake pass into the Schroon 

 river and thence to the Hudson. Boreas ponds are the sources of 

 the Boreas river which goes to the Hudson direct. Avalanche lake 

 just east of Mount Maclntyre is one of the ultimate sources of the 

 Hudson itself. Its outlet throvigh Lake Golden and the Flowed 

 Lands is the Opalescent river, which with many feeders from the 

 Mount Marcy group of mountains passes into Lake Sanford, on 

 whose eastern shore are the famous bodies of titaniferous magnetite. 



North and southeast of Mount Dix are the sources of the Boquet 

 river which passes through Elizabethtown and thence to Lake 

 Champlain at Willsboro. All the other streams feed into the two 

 branches of the Ausable river, which unite at Ausable Forks and 

 traverse the famous chasm into Lake Champlain, south of 

 Plattsburg. 



Except those portions of the streams which practically belong to 

 the lakes or ponds, all are swift in current, with rather steep gradi- 

 ents. In the small brooks are several cascades or waterfalls with a 

 sufficient drop to afford very picturesque bits of scenery. In the 

 larger streams but two cascades are worthy of comment. Both 

 are on the East branch of the Ausable river; one, a m.ile and a half 

 above Keene Center, and another just below the first. The i^iver 

 pours over rocky ledges in each instance, while elsewhere its course 

 is usually over a bouldery bottom of drift. There is some ground 

 for the inference that the rocky ledges mark postglacial portions of 

 the channel, although no positive evidence in the way of borings 

 is at hand of buried water courses rvmning around the ledges. This 

 subject is more fully treated toward the close of the bulletin in 

 the chapter on the Pleistocene. The large valleys were undoubtedly 

 existent and of approximately their present size in preglacial times, 

 ajid the large features of the topography were earlier blocked put. 



