GEOLOGY OF LAKE PLEASANT QUADRANGLE 63 



course of the tributary Kennyetto creek is due to a deflection of 

 the lower reach of the stream down the north slope of the same 

 morainic dam above mentioned. 



Another very interesting drainage feature is the following. Within 

 the quadrangle, Fawn lake and Sacandaga lake are only half a 

 mile apart and yet the waters pass off in opposite directions, the 

 drainage from Fawn lake flowing westward and southward through 

 Fall stream, Piseco lake, Piseco outlet, and West Branch to its 

 mouth, or a distance of over 30 miles, before meeting the drainage 

 from Sacandaga lake. 



Lattice drainage. A glance at the geologic map will show that 

 most of the important stream channels of the quadrangle have 

 been developed along fault lines of weakness. Professor Brigham 

 has applied the term " lattice drainage " to a more or less regular 

 or latticeHke system of drainage lines due largely to a development 

 of stream courses along intersecting faults. The whole area of the 

 Lake Pleasant quadrangle is a good illustration of such " lattice 

 drainage," that portion lying between Wells and Hamilton lake 

 being particularly good. No doubt other faults than those shown on 

 the map, especially minor east-west ones, exist, so that the full 

 influence of the faulting as a cause of the " lattice drainage " is 

 not brought out. Also the very strong northeast-southwest trend 

 of the mountain ridges due to faulting and the consequent general 

 tendency of the little streams to enter the fault valleys at right 

 angles, helps to bring out the lattice form of the drainage. 



GLACIOLOGY 

 During the Glacial epoch, the area of the quadrangle was buried 

 under the great ice sheet as proved by glacial marks or striae, 

 boulders, and morainic deposits. At the time of maximum glacia- 

 tion, the whole Adirondack region, even including the highest peaks, 

 as well as practically all the rest of the State, was covered by this 

 ice sheet. 



Ice movement and erosion 



As is well known, the general movement of the ice was from 

 the Canadian region southward over New York State. Across the 

 quadrangle the direction of the flow varied from southwestward 

 to southward. Nine sets of glacial striae have been observed and 

 plotted upon the map. They are distributed as follows : 

 I S 45° W, on the roadside i^ miles northeast of Lake Pleasant 

 village. 



