492 NEW YORK STATE MUSEUM 



of the topographic map shows that in both the northern and 

 southern highland areas the hill summits tend to elevations of 

 from 2600 to 2800 feet, with the Kempshall and Morris summits 

 alone overtopping that elevation as small monadnocks [pi. 5, 6, 14]. 

 A study of the topographic maps of the adjacent quadrangles how- 

 ever quickly dispels the impression that we have here a peneplain 

 level which can be shown to extend over any considerable area. 

 On the St Regis quadrangle, just north, but a single hill (St Regis 

 mt, 2882 feet) exceeds 2600 feet elevation, and there are but two 

 others which reach 2500 feet, most of the hills ranging from 1900 

 to 2200 feet. There is further seen a range of hills running across 

 the quadrangle from northeast to southwest east of which lies a 

 depressed belt, the lake belt, in which the hilltops little exceed 

 1800 feet, yet the rock is anorthosite, as it is in the higher range 

 to the west. This lake belt seems a downfaulted trough, and its 

 southward prolongation forms the northwest portion of the Long 

 Lake quadrangle. The altitudes of the hill range are fairly con- 

 cordant with those of the highlands on the Long Lake quadrangle. 

 In both the valley levels are near 1600 feet, indicating that the 

 dislocation of the peneplain surface by faulting dates mainly 

 from the time of the first uplift which followed its formation. 



On the Santanoni quadrangle, adjoining the Long Lake on the 

 east, there are several peaks over- 4000 feet high, the main water- 

 shed of the region appears, and we are carried at once into the high 

 Adirondacks. There are no elevations concordant with those on 

 the Long Lake sheet, and there are many things which suggest 

 considerable faulting. Because of proximity to the watershed 

 the valley levels are also higher, but seem fairly concordant, taking 

 this into consideration. 



South, on the Blue Mountain quadrangle, are many peaks with 

 altitudes well over 3000 feet, with Blue mountain, 3759 feet, 

 overtopping them all. There are also many lower hills which 

 are more in accord with the general Long lake altitudes. Whether 

 the higher hills are to be classed with Kempshall and Morris as 

 monadnocks, in which case they would be very numerous, or 

 whether they represent the peneplain level, dislocated out of 

 accord with the Long lake levels, is not certain. 



Topography as conditioned by the rocks. Owing to their weak 

 resistance to erosion, in comparison with the other rocks of the 

 region, the Grenville rocks give rise to valleys, and the main 



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