GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 23 



15° S. 17° W. This possesses peculiar mineral characters, whose de- 

 scription is reserved for another chapter. A small dyke cuts this, and 

 seems to have determined the course of the Silver stream, as may be 

 well seen in the heliotype of this cascade. Two or three hundred feet 

 above the road I observed a mass of mica slate, ten feet long, seven feet 

 wide, and three feet thick, imbedded in the granitic rock, and smaller 

 pieces of the same material may often be seen enclosed in this matrix. 

 Veins of feldspar show themselves higher up. After getting well up on 

 the flank of the mountain, among the small trees, there is a series of 

 pools along the brook where foliated planes of mica schist dip 70° N. 

 57° E.; but these may not be the lines of stratification. This soon passes 

 into the usual rock of the range, continuing to the crest of the ridge, 

 dipping 70° north-westerly. The route taken may be understood by re- 

 ferring to the heliotype opposite page 79, Volume I. We passed through 

 the Notch, leaving the Elephant's Head to the left, and at about a quarter 

 of a mile below the Gate commenced the ascent, taking a direct course 

 for the highest part of the central mountain in the background. The 

 common rocks of the Montalban group occupy every part of this view 

 to the left of the Gate, and a short distance to the right. The beginning 

 of the steeper slope very near the summit of Mt. Webster indicates the 

 line between the ferruginous mica schists on the left, and the eruptive 

 granites of the Pemigewasset series on the right. 



On the top of Mt. Webster the rock is the ferruginous variety ob- 

 served on Mts. Pleasant and Franklin, traversed by veins of two or three 

 feet thickness of coarse granite and dykes of white-colored trap. South 

 from the north edge of the mountain the dip of the schists is 70° N. 6^° 

 E. One can walk along the crest of this ridge and enjoy a fine view of 

 the Saco valley below Mt. Willard. The summit is devoid of trees ; and 

 there is a precipice several hundred feet deep which is entirely composed 

 of the schists. At its base the granite begins ; and the difference be- 

 tween them is marked still further by a great contrast in color, — reddish- 

 brown against grayish-white. Opposite the Willey house the strata may 

 be said to dip westerly, though, as the dip varies but a few degrees from 

 perpendicular, the occurrence of a leaning to the east or west cannot be 

 of much consequence in the study of the stratigraphical position. The 

 small variations are often due to disturbances induced in connection with 



