GEOLOGY OF THE LAKE PLACID REGION 53 



several peaks in the immediate vicinity are as follows: White- 

 face, 4872; Sentinel, 3858; Pitchoff, 3450; Cascade, 4092; Por- 

 ter, 4070. Mt Mclntyre, at 5112, can be reached and ascended iu 

 a day, and is second only to Mt Marcy at 5344. Of all the Adi- 

 rondack peaks, these two alone, Mclntyre and , Marcy, exceed 

 5000 feet but several others approximate it closely. 



Of the minor elevations near the lake. Eagle Eyrie is 265G, 

 Pulpit mountain 2658, the two being practically the same, and 

 Cobble hill is 2330. 



ROCKS 



The rocks proper, which include the ^ hard ' formations as con- 

 trasted with the incoherent sands and gravel, may be classified 

 into 1) crystalline limestone, 2) quartzite, 3) granite, 4) gneiss, 

 5) anorthosites or the rocks consisting chiefly of labradorite feld- 

 spar, 6) trap dikes. If we add the incoherent sands and gravels, 

 there are, 7) moraines of unsorted sands and boulders, large and 

 small being commingled, and 8) water-sorted sands and gravels, 

 forming abandoned lake bottoms and deltas now more or less 

 modified by erosion both by wind and water. 



Crystalline limestone. This" rock is not in large amount but 

 it is extremely significant in its geologic relations. Keference 

 to the geologic map (cover p. 2) will indicate its presence in only 

 one place so far as known in the town of North Elba and that is 

 near the trail that leaves the Wilmington road at the house of 

 Mr Watson. A small area outcrops in the bottom of a brook. In 

 the valley of the east branch of the Ausable river, one outcrop 

 occurs in the town of Jay. There are at least six or seven in 

 Keene. The limestone is always a coarsely crystalline variety, 

 and is formed of rather large individuals of calcite, through 

 which smaller crystals of pyroxene, of the variety coccolite, are 

 richly distributed in practically all cases. Graphite is often 

 present and dark bunches of varying size consisting of black 

 hornblende, quartz, pyrrhotite, feldspar and some rarer minerals 

 are frequent. Traces of bedding have been destroyed and al- 

 though the limestone shows as a rule a banded character, this 

 is the result of pressure exerted during its metamorphism. The 



