THE ADIRONDACK MOUXTATXS 63 



Like glacial erosion, the deposition of glacial materials has not 

 changed the major topographic features of northern New York. 

 The general tendency of ice deposits has been partially to fill depres- 

 sions and thus to diminish the ruggedness of the relief. 



Origin of the lakes. The numerous Adirondack lakes constitute 

 one of the most striking differences between the geography of the 

 present and that of preglacial time. Before the Ice Age practically 

 none of the lakes was in existence, the bodies of water having been 

 produced either directly or indirectly by glacial action. Among the 

 methods of lake basin formation were building dams of glacial debris 

 across old river channels or valleys ; ice erosion ; and the production 

 of depressions by irregular accumulation of glacial debris or by the 

 melting of large blocks of ice which were more or less submerged 

 under glacial debris. 



Most of the lakes were formed by dams of glacial material thrown 

 across valleys. It is quite the rule to find the outlets of these lakes 

 flowing through loose materials of this sort. By ice erosion, many 

 of the favorably situated valleys were somewhat modifiied, but there 

 are few, if any, lake basins produced wholly by that process. There 

 are many examples of ponds and small lakes which occupy depres- 

 sions below the general level of certain sand flats, the sands having 

 been deposited in glacial lakes during the retreat of the ice, and the 

 depressions resulted from the subsequent melting of blocks of ice 

 which were surrounded by the sand deposits. Numerous examples 

 of such ponds occur within the St Regis quadrangle and on the great 

 sand plain along the eastern side of the Black River valley. 



Sometimes small lakes or ponds are situated well up on high 

 mountains. Examples are on Crane mountain (North Creek quad- 

 rangle) at 2620 feet; Morgan pond on Wilmington mountain (Lake 

 Placid quadrangle) at 3020 feet; on the mountain 1^2 miles due 

 north of Indian pass (Santanoni cpadrangle) at 3550 feet; and the 

 Wall Face ponds i mile northwest of the same Indian pass at 3040 

 feet. Perhaps highest of all is Lake Tear, sometimes called Lake 

 Tear of the Clouds, at 4300 feet close to the divide between Mt 

 Marcy and Mt Skylight. This is one of the sources of the Hudson 

 river. 



Many of the Adirondack lakes were formerly larger, as proved 

 by delta deposits above the present lake levels. Two examples which 

 have recently come under the writer's observation are Schroon lake 

 and Piseco lake. The water of Schroon lake was once fully 70 feet 

 higher when it extended some 8 or 10 miles farther up the Schroon 

 valley with an arm reaching over the area of the present Paradox 



