I38 NEW YORK STATE MUSEUM 



the north today. The writer has determined the amount of tilt for 

 a number of different glacial lake levels by direct measurement and 

 has shown that very probably the land was experiencing uplift while 

 the lakes were in existence, and thus each successive lake level has a 

 slightly different degree of tilt, being greater for the higher lakes 

 than for those lower down in a given series. 



This subject is introduced here, for it has a possible bearing on 

 the origin of Lake Clear and its shore materials. 



The Lake Belt 



Lake Clear lies in what has been called the " Lake belt " through 

 which, in preglacial times, the streams had their courses. The 

 countless number of lakes " range in size from fairly large bodies of 

 water, several miles long and a mile or two in width down to the 

 most insignificant of ponds." 1 Most of them " have received a 

 north to northeast alinement from the faults " as is easily seen in 

 " Upper and Lower Saranac, Big and Little Tupper and Long lakes." 1 

 Placid, Cranberry and Raquette lakes represent a " somewhat 

 different type in that they seem to occupy portions of more than one 

 valley." 2 



" There are rock islands ... in all these larger lakes and 

 often in considerable number." Lower Saranac and Big Tupper 

 are full of them " alined so as to suggest the drowning of adjacent 

 small valleys." 3 



The outlets of many of the lakes in the region are over ledges of 

 the old igneous rocks. " Thus the level of Upper Saranac lake is 

 maintained by the ledge of anorthosite over which its outlet pours 

 at the Bartlett Club House; Lower Saranac has its outflow directly 

 into the Raquette, and the level of that stream is determined by 

 the ridge at Piercefield." 4 Other lakes owe their origin to morainal 

 dams blocking valleys, while still others, especially the smaller ones, 

 occupy kettle holes. A few occupy rock basins. Nearly all the 

 lakes in the Lake Clear region are situated in depressions in the 

 Saranac glacial water plain. 



1 H. P. Cushing, N. Y. State Mus. Bui. 95, p. 429 and 445. 



2 H. P. Cushing, N. Y. State Mus. Bui. 95, p. 445-46. 



3 Op. cit. 



4 H. P. Cushing, " Preliminary Report on the Geology of Franklin County," 

 pt. 3, 1 8th Rep't N. Y. State Geol., p. 83. 



