22 NEW YORK STATE MUSEUM 



thence it swings abruptly westward into southern FrankHn and 

 northwestern Hamilton counties ; and thence southward clear 

 through Hamilton county. Toward the north two deep, narrow 

 valleys have been cut across the main axis by the two chief branches 

 of the Saranac river. From there southward the two lowest 

 passes across the main axis of elevation are long relatively broad 

 valleys with maximum altitudes of about 1800 feet, one extending 

 east-west across the northern part of the Blue Mountain quadrangle, 

 and tlie other east-west through Raquette and Blue Mountain 

 lakes. 



Valleys 

 It is almost impossible to think of the mountains apart from the 

 valleys. Like the mountains, the Adirondack valleys are also 

 exceedingly variable in size, shape and distribution. In general there 

 are three types of valleys, one of which is broad, open and usually 

 of irregular shape; the second type is moderately wide, relatively 

 long and more regular in shape; while the third type is deep, nar- 

 row and often comparatively straight for some miles. Large scale 

 examples of the first type are the valleys : south to southeast of 

 Lake Placid; around Saranac lake; in the vicinity of Newcomb; 

 from Blue Mountain lake eastward to Rock lake ; the region around 

 Indian Lake village ; and in the vicinity of Lake Pleasant. These are 

 all some miles across. Large valleys of this sort owe their origin 

 almost entirely to the removal of irregular masses of relatively 

 weak rock by weathering and erosion. Many smaller open valleys 

 of irregular- shape have also been produced in this manner. The 

 open, more regular valleys belonging to the second type are con- 

 fined chiefly to the southeastern half of the Adirondacks, most of 

 them having resulted from the settling of earth-blocks along or 

 between lines of fracture (faults). Excellent examples are the 

 valleys in part occupied by Piseco, Indian and Schroon lakes, and 

 also the remarkable valley at Wells (Hamilton county) which is a 

 wedge-shaped block of earth, several miles long, dropped at least 

 2000 feet between two earth fractures (see figure 9 and explana- 

 tion on a succeeding page). There are, to be sure, occasional 

 valleys of this second type which have been produced by ordinary 

 erosion instead of by faulting. The deep, narrow, relatively straight 

 valleys of the third type have resulted for most part in either of 

 two ways, namely, by ordinary erosion where certain streams have 

 been favorably situated as regards volume and velocity of water, 

 or by stream erosion along zones of hard or soft rocks which have 



