Gushing — Potsdam Boundary. 7 



upon it along the streams or the shores of the higher water levels which 

 accompanied and followed after the withdrawal of the ice-sheet from northern 

 New York. 



The water-shed between the lake Champlain drainage and that direct 

 to the St. Lawrence, passes from north to south through Clinton county 

 close to the Franklin county line, till it veers to the south-westward into 

 Franklin county just south of Upper Chateaugay lake. On this watershed the 

 basal Potsdam reaches an altitude of about 1100' A. T. Thence westward 

 along the boundary it decreases steadily until south of Potsdam city it 

 lies at an altitude of from 700' to 800' lower. This discrepancy must neces- 

 sarily be due to differential uplifting since its deposition. 



The largest streams, like the Racquette, St. Regis, Salmon and Chateaugay 

 rivers flow in narrow valleys cut in the drift, and in still narrower rock gorges 

 where they are out of their old channels. They are all actively engaged in 

 deepening their channels and cutting back the rapids at the head of the gorges. 

 The gorge of the Chateaugay is, in impressiveness, second only to the Ausable 

 Chasm in the Adirondack region. The more westerly streams have less fall 

 and are not cutting so actively. 



The Glacial Deposits. 



Only general attention could be given to the drift deposits, so that the 

 hap-hazard observations made would not be commented on, were it not for the 

 fact that the deposits are of great interest and are but little known. 



Over a wide area north of the Adirondacks the drift proper is submerged 

 beneath heavy sand deposits, the conditions being very similar to those pre- 

 vailing in Clinton county near lake Champlain. The sands are of course 

 mainly along the stream valleys but have considerable w T idth on each side and 

 become confluent when the streams are not far apart. Morainic knobs and 

 ridges protrude through them here and there and cuts often show the under- 

 lying drift. The north and south roads in northern Franklin county and the 

 adjacent part of St. Lawrence county are commonly near enough to some 

 stream to make the roads excessively sandy, and driving over them is a most 

 irksome task. The cross roads pass over the divides between the streams and 

 are better. 



These sands are found abundantly at certainly three, and probably four 

 distinct levels and the descent from one level to another is sometimes quite 

 abrupt, the sand plains rising in terraces, one above another. This is well 

 shown just north of Malone, where the sand plain stretching north from the 



