GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 183 



Above the railroad, and the same rock occurs both north and south 

 along the track for a considerable distance, is a red compact granite, 

 apparently one of the varieties of the Conway series. With slight mod- 

 ifications this rock occurs all the way up to Tuckerman's falls, eight hun- 

 dred feet above the road. It is usually much permeated with joints. At 

 the "Stair falls," some of these joints dip ten degrees easterly. Higher 

 up the dip is from twelve to fifteen degrees S. 32° E. A sj^ecimen from 

 one and a half miles up is like the Frankenstein granite. Two kinds of 

 dykes up this brook are peculiar; the first, two miles up, of compact 

 feldspar; the second, half a mile beyond, of trap containing fluorite and 

 calcite. Still higher, at the falls forty or fifty feet high, there is a trap 

 dyke from four to ten feet wide, dipping 80° N. 87° E. Tuckerman's 

 falls are one hundred and twenty feet high. Mr. Huntington says the 

 rock all the way up Bcmis brook, and thence over the mountain to Rip- 

 ley's falls, and down Cow brook to the road again, is of the Conway 

 variety. This journey was taken in July, 1875. Mr. Galbraith went up 

 Davis brook to a peak opposite Mt. Crawford, thence north-west to 

 another mountain, thence south-west to Nancy mountain, and reports all 

 the ledges as composed of granite. The specimens from Nancy pond are 

 a fine-grained variety of the Conway series, containing much quartz. 

 This variety prevails in the neighborhood (see p. 146). At a mile east 

 of Nancy pond the granite is reddish and coarse grained. It is con- 

 tinuous with that which is typical of the series at Bemis pond, and so on 

 to Green's cliff and the Swift river interval in Albany. 



Still another variety of granite, related to the Albany, is developed 

 adjacent to the gneiss, an eighth of a mile north of Bemis station. It is 

 composed of crystals of orthoclase and quartz, usually an eighth or a six- 

 teenth of an inch in diameter, with a yellowish tint, verging to light gray. 

 It is necessary to cleave this and the spotted granite in a particular way, 

 in order to exhibit the crystalline faces perfectly. When broken other- 

 wise, the presence of perfect crystals in the mass is not evident. These 

 granites holding crystals will be described fully in the mineralogical part 

 of this report ; and they will be noticed also in the discussions likely to 

 be presented subsequently respecting their origin. 



