GEOLOGY OF THE NORTH CREEK QUADRANGLE 75 



POSTGLACIAL DRAINAGE CHANGES 



Aside from the destruction or partial destruction of glacial 

 lakes by cutting down the outlets or filling them up or both, and 

 the moderate amount of downcutting by the larger streams with re- 

 sulting development of terraces, there appear to have been no im- 

 portant drainage changes. Due to the irregular distribution of the 

 glacial drift many of the small streams have postglacial courses, 

 but the larger streams, like the Hudson and Schroon rivers, are 

 believed to follow practically their preglacial channels which are 

 well adjusted to the character and structures of the rock masses 

 over which they flow. 



In a recent paper ^ the writer discussed certain important post- 

 glacial drainage changes in the southeastern Adirondacks, and since 

 one of the changes concerns the Hudson river immediately after it 

 leaves the North Creek sheet, a very brief statement will here be 

 made. 



Instead of the present long, circuitous course of the Hudson 

 river past Stony Creek, Luzerne, Corinth, and thence across the 

 Luzerne mountain to Glens Falls, the preglacial Hudson certainly 

 took a shorter course, most likely through the channel from War- 

 rensburg to Caldwell and thence to Glens Falls. 



The great gorge of the Hudson above Stony Creek station is 

 surely of either interglacial or postglacial origin and in its stead 

 a preglacial divide was located there. Evidences favoring this view 

 are given in the paper above cited. 



Since the preglacial Hudson river did not flow southward across 

 the Luzerne sheet, it must have flowed eastward across the low 

 mountain ridge between Warrensburg and the Lake George de- 

 pression. There are but two possible channels there, namely: the 

 Warrensburg-Hillview channel and the Warrensburg-Caldwell chan- 

 nel. In the paper above cited, arguments are presented to show 

 that the latter channel was the more likely one. The preglacial 

 Hudson was joined by the Schroon just east of Warrensburg, while 

 a short tributary, having its source on the Stony Creek divide, flowed 

 northward into the Hudson. An important preglacial stream, called 

 the Luzerne river by the writer, had its source on the Stony Creek 

 divide and flowed southward past Luzerne and Corinth and through 

 the broad valley west of Saratoga Springs. 



1 Preglacial Course of the Upper Hudson River, Geol. Soc. .\mcr. Rul. 

 191 1, 22: 177-86. 



