GEOLOGY OF THE PARADOX LAKE QUADRANGLE 467 



suggests faulting, and its direction (s. 15 w.) suggests a later origin 

 than that of the Cambric valleys, whose direction is slightly north 

 of east. 



The invasion of the Potsdam sea from the east suggests that these 

 Prepotsdam rivers flowed toward the east. This is further borne 

 out by the attitude of the rock beneath the drift, so far as it is known, 

 and by sounding in the lakes. In Goose pond, Crane pond, Pyramid 

 lake and Chilson lake soundings showed a slightly greater depth 

 of the rock bottom in the eastern than in the western ends. An 

 uplift of 25 feet in the western part of the quadrangle would reverse 

 the drainage of several important streams. The Chilson lake valley, 

 after such an uplift, would drain eastward into Penfield pond ; Goose 

 pond would drain into Crane pond and Crane pond eastward 

 through Rock pond to Putnam creek; Black brook would pass east- 

 ward until diverted by the Knob mountain fault. After a recon- 

 struction of the country, and after removing all drift and replacing 

 all faults, this easterly direction of drainage becomes universal. If 

 the faulted face of Treadway mountain were removed Pharaoh lake 

 would drain through a wide and now dry valley into Putnam pond. 



The conclusion is that the drainage was established when Cam- 

 bric time opened; that the general direction of drainage was east- 

 ward, usually northeast, occasionally southeast; that the streams at 

 this time were adjusted to the limestone, and that the region was 

 mature. 



The alternative hypothesis, that the region was a peneplain in 

 Cambric time and the outliers dropped by faulting, seems untenable 

 in the light of these various lines of evidence. There is no evidence 

 of such faults, but every indication, short of absolute proof, that 

 the valleys containing the outliers were normal erosion valleys estab- 

 lished on the limestone. 



Of the events of later Palaeozoic time there is little evidence 

 within this quadrangle. Abundant fragments of Calciferous and of 

 Trenton rocks suggest that the region was entirely submerged. An 

 outlier of the Calciferous is found at Schroon lake, but none within 

 the limits of the Paradox Lake quadrangle. 



