GEOLOGY OF FRANKLIN COUNTY 83- 



Drainage 



Lakes. Though lakes are of frequent occurrence throughout the 

 Adirondack region, there is a belt Of territory in southern Frank- 

 lin and northern Hamilton counties in which they are far more 

 numerous than elsewhere. ,In Franklin county they can be 

 enumerated by the hundred, and range from fairly large bodies of 

 water, several miles long, down to the most insignificant of ponds. 

 Very few data are available concerning them, and they would, 

 well repay the careful study which could not be given them in a 

 hurried trip through the district during which the attention was 

 centered an other problems. 



The lakes are massed in greatest number along the watershed 

 of the main streams, and do not differ greatly in altitude. This 

 watershed is produced by the highest altitudes reached by the 

 drift in the old valley bottoms and is to a certain degree independ- 

 ent of the main axis of the hills. The belt of abundant lakes at 

 the headwaters of the streams is due to the high level dams formed 

 by rock ledges, which lie across their courses farther down. The 

 outlets of the lakes are in new channels and have encountered 

 ledges of rock through which they must cut. 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 

 lake is held up by the ledges south of the village; Big Tupper lake 

 has its outflow directly into the Raquette, and the level of that 

 stream is determined by the rock ridge at Piercefield. 



The larger lakes have rock-bound shores for the most part, and 

 occupy the full width of the valley in which they lie. The lesser 

 lakes may or may not have rocky shores, according as they lie in 

 narrow or wide valley s, or whether the hollow in which they 

 nestle lies in the center or toward the side of the valley. 



The origins of these lakes are as various as the causes which 

 produce irregularities in the drift surface. The larger lakes 

 occupy portions of old stream valleys, which they fill from side to 

 side, and are held in place usually by morainic dams across the 

 valley. Some of the smaller lakes occupy kettle-holes in the 



