180 W. J. MILLER PREGLACIAL COURSE OF UPPER HUDSON RIVER 



than soft Grenville rocks, which are so common farther northward, and 

 the. apparent lack of faulting and the fact that the course of the river is 

 nearly at right angles to the strike of the foliation, whereas faulting and 

 foliation have elsewhere in the region been important factors in deter- 

 mining stream channels. 



Between Corinth and Glens Falls the Hudson cuts across the Luzerne 

 Mountain, and, as shown by Wright in the paper above cited, this course 

 is certainly either inter-Glacial or post-Glacial in origin. This matter 

 may be discussed to better advantage below in connection with the 

 Luzerne Eiver. 



PRE-QLAGIAL COURSE 



That the pre-Glacial Hudson, between North Creek and Warrensburg, 

 flowed in practically the' same direction as at present is shown by the fact 

 that it occupies a broad general depression, which is in harmony with the 

 character and structure of the rock-masses.* This broad depression is 

 characterized by an abundance of weak Grenville gneisses, through which 

 protrude more resistant masses of syenite or granite. Other important 

 factors of drainage control here are the extensive faulting and the strike 

 of the foliation, both of which are in general north and south. Also, it 

 should be stated, that distinct highland masses preclude the possibility of 

 any other than a southward course of the pre-Glacial Hudson across the 

 North Creek sheet. Below Warrensburg, however, the pre- and post- 

 Glacial courses of the Hudson are very different. It has already been 

 shown that the pre-Glacial Hudson did not flow across the Luzerne quad- 

 rangle, and it now remains to locate its pre-Glacial channel elsewhere. 



Between the Hudson-Schroon Eiver and the Lake George depression 

 there is a highland belt or mountain ridge which, towards the south, is 

 known as the Luzerne Mountain. The pre-Glacial Hudson must have 

 crossed this mountain ridge, and there appear to be but two possibilities 

 for an old channel here. One of these is the depression which strikes 

 northwest-southeast between Warrensburg and Caldwell, while the other 

 runs nearly east and west between Warrensburg and Hill view (on Lake 

 George). 



Some of the considerations favoring the Warrensburg- Caldwell channel 

 are: (1) Lower elevation (not over 840 feet) of the divide in this de- 

 pression; (2) the nearness (1% miles) of this divide to the Schroon- 

 Hudson river bottom and its distance from Lake George, which is what 

 would be expected, because a river flowing southeastward through this 



* Some interesting drainage changes in the course of the Hudson above North Creek 

 have been described by Prof. J. Kemp in "The Physiography of the Adirondacks." 

 Popular Science Monthly, March, 1906, pp. 205-206. 



