328 NEW YORK STATE MUSEUM 



the region about the outlet of Lake George, the.se are by no means 

 inconsiderable. The anorthosites occur in general throughout a 

 broad belt, which extends from Port Kent and Saranac Lake, south- 

 westerly 60 or 70 miles. The anorthosites do not form a solid belt, 

 as is the general impression, but are found in ridges of northeast- 

 erly trend, with gneiss and crystalline limestone almost always appear- 

 ing in the valleys. Still around Mt Marcy there is a great group 

 of peaks and no gneiss or limestone has been found in between them. 



The relief of the country is not entirely due to erosion, although 

 this has been extensive both by water and ice. One can not resist 

 the conviction when viewing the dome-shaped peaks or knobs, that 

 they are in a large part due to block faulting, and the steep cliffs of 

 Adirondack Pass, of Avalanche Pass and many others, confirm the 

 impression. The remarkable shear-zone at Avalanche Lake* is also 

 an additional proof. In the iron mines it has been a frequent 

 experience to find the ore body cut off by a fault where it has been 

 followed under a gulch. What is true for the small depressions is 

 doubtless applicable on a large scale. The mountains repeatedly 

 have a much steeper eastern face than western, as if presenting to 

 the east, old, eroded, fault-scarps. Erosion both by water and ice 

 has contributed its share in modifying contours, so that now the 

 angles are largely rounded off. 



Over the whole country is spread the drift, either sorted or 

 unsorted, and no more striking exhibition of it is to be found in the 

 United States, than in the Adirondacks. As a general thing, aside 

 from the mountains, the country is extremely sandy, and often in 

 the valleys shows unmistakable evidence of having once been lake- 

 bottoms,! on whose shores the deltas still remain. 



GENERAL STRATIGRAPHY 



The stratigraphical relations of the Archean crystalline rocks are 

 obscure as decisive evidence is not easy to procure. In the writer's 

 opinion we have the same succession as in Canada, where the Ottawa 

 Gneiss is the lowest member ; the Grenville Series of more schistose 

 rocks and limestones lies over it ; and through both these are 



*J. F. Kemp. The great Shear-zone at Avalanche Lake. Anier. Jour. Sci. 

 Aug. 1892, p. 109. 



f H. Ries. A Pleistocene Lake-bed at Elizabethtowu, N. Y. Trans. N. Y 

 Acad. Sci. Nov. 1893. 



