REPORT OF THE DIRECTOR I9IO 1 89 



1400 to 1500 feet above the Hudson river, which flows at their 

 base. The domes proper, however, range in height from 400 to 600 

 feet. 



Mill and Stockton mountains deserve special mention because 

 they rise as two great isolated masses above the comparatively low 

 and featureless country in the vicinity of Johnsburg and Wever- 

 town. Each rises abruptly some 600 or 700 feet above the sur- 

 rounding country and they attain altitudes of 1949 and 1837 feet, 

 respectively, above the sea. 



Huckleberry and Crane mountains are completely separated by 

 a narrow rift from 500 to 800 feet deep. The summit of Crane 

 mountain (3254 feet) rises 2000 feet above the immediately sur- 

 rounding lowlands and it is the highest point in Warren county. 

 The upper 1000 to 1500 feet of this mountain is very steep to 

 almost precipitous on all sides except the north and this great rock 

 dome is a grand sight as viewed from Thurman. 



The domes may be classified under three headings according to 

 shape: (i)those with nearly circular, bases and which are very 

 symmetrical and almost uniformly steep on all sides as, for example, 

 Potash, Mill, and Stockton mountains and the top of Kelm moun- 

 tain; (2) those with elliptical bases and represented by nearly con- 

 centric elliptical contours to the summit, such as Moon, Birch, 

 No. 9, and Huckleberry mountains : Moon mountain is a good 

 illustration of the broad elliptical type, while Huckleberry moun- 

 tain is a fine example of the long, narrow, elliptical type ; these 

 elliptical forms are the most common and usually have one side 

 very steep due to faulting; (3) those of irregular shape as shown 

 on a large scale by Crane mountain and by many smaller masses. 



After climbing many of the domes the writer had been impressed 

 by the almost universal occurrence of exfoliation on a large scale 

 over their surfaces. These mountains are literally peeling or shell- 

 ing off by the removal of exfoliation sheets of great size, some hav- 

 ing been noted as much as 50 to 75 feet across and from i to 3 feet 

 thick. Among many other good places to observe this phenomenon 

 are on the west or south sides of Moon, Huckleberry, or Crane 

 mountains. Not infrequently, especially during the fall and spring 

 months, slabs loosen up and go thundering down the mountain 

 sides. Though the igneous rocks are all clearly gneissoid, the ex- 

 foliation appears to entirely disregard the direction of the gneissic 

 structure and often great sheets come off at right angles to the 

 foliation. 



