CuSHESTG — GrBOLpGY OF Cl.IXToN COUNTY. 



a\ it li the hilly tract, and slopes thence gently northward to the brink of the 

 St. Lawrence valley. The surface rock throughout in this county is the 

 Potsdam sandstone which lies nearly horizontal, having but a slight 

 northerly dip, so that its descent is not greatl y in excess of the average surface 

 fall. The covering of glacial material is widespread hut mostly confined 

 to the depressions, and the numerous, often large, marshy tracts testify to its 

 irregularity. 



The streams draining northward across the plain have for the most part 

 not channelled it very deeply since the close of the glacial period, on account 

 of the horizontal attitude of the rocks and their resistant character. During 

 the late Tertiary, the plain was much dissected by the drainage, but even 

 then the valleys were relatively narrow, the present summits of the plain 

 consisting of comparatively wide table lands of sandstone instead of narrow 

 rid oes and mounds. The new maps cover a portion of this plain in Mooers 

 and Altona and indicate that these summits represent portions of an earlier 

 base level, now tilted to the north. 



."). A low strip along the lake, ranging from the lake level to an altitude 

 of 300 feet on its western border, and increasing in breadth going north. 

 From the 300 foot to the 500 foot level, the rise is quite abrupt, especially in 

 ('hazy township, and the topography strongly suggests a fault, raising the 

 Potsdam on the west some hundreds of feet above that on the east, and 

 marking the boundary between the low strip and the high plain. Further to 

 the south, the heavy Pleistocene deposits largely obliterate this contrast. 

 This low strip is greatly dissected by faults, and to their presence its 

 minor topographic features are largely due. The fault lines are occu- 

 pied by marshes or small streams, while between them ledges of rock 

 project at all angles in a seemingly haphazard and at first, quite bewildering 

 fashion. 



Throughout this low strip the main streams quite generally follow their 

 pre-glacial channels. The Saranac and Great Chazy rivers have channelled 

 out considerable valleys in the drift and are now widening them. The Great 

 Chazy river is in its pre-glacial channel throughout the low strip, exposing 

 nothing but drift in its banks. At Mooers village it leaves the old channel 

 for a short distance, and thence up-stream this frequently happens, but this 

 channel belongs topographically to the high plain. The Saranac is out of its 

 old course at the pulp mill, two miles above Plattsburgh, thence keeps to its 

 old valley till Cadyville is reached. Here a considerable gorge has been cut 

 in the Potsdam, but this is beyond the confines of the low strip. 



