GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 69 



mountains. The lower junction of this granite with the IVIontalban is 

 concealed by drift, but the strata of the latter are distinct, standing ver- 

 tical, with the strike N. 42° W. They are better characterized than those 

 above, though they do not extend more than 1 200 feet before a change 

 ensues. 



The fact of greatest importance in regard to the granite remains to be 

 mentioned. Following the railroad to where it would naturally be inter- 

 sected by the Butterwort dyke, or 4700 feet from the Crawford station, 

 we come to a breccia of enormous pieces, five or six feet long, and less, 

 the fragments consisting entirely of the hard Montalban schists, while 

 the cement is of the variety of granite just mentioned. One can see 

 that it has found its way between large pieces that naturally fit together. 

 This breccia extends for 1200 feet along the railway, but it does not appear 

 much higher on the mountain. Between it and the exposure of schists 

 at the summit only granites appear. Something of a breccia character 

 in the Montalban schists has already been mentioned in the description 

 of the upper part of Mt. Washington river ; and at the Notch cuttings, 

 imbedded pieces of the schist in the granitic portions are not rare. It 

 forcibly reminds us, however, of the Franconia breccia, thought to 

 mark the close of the Montalban period ; and we have recently described 

 also masses of the same rocks imbedded in the Conway granite above 

 Beecher's cascades. As a matter of convenience, I propose to call this 

 cementing material the Bi'eccia granite, to distinguish it from the many 

 other varieties of this rock in the White Mountains. 



The next rock seen along the railway is the well-known Conway gran- 

 ite, already mentioned as constituting the summit of Mt. Willard, and fol- 

 lowing up the valley of the Saco to about the 1 500 feet contour line. It 

 occurs along the railroad for 1 300 feet, and makes up the greater part of 

 the south precipitous exposure of the mountain. Its features are pre- 

 cisely the same as if it occurred in Conway or Franconia. On one large 

 ledge the crystals of quartz seemed uncommonly abundant. Its union 

 with the spotted granite, as well as the boundaries of the slaty breccia 

 and slate along the railroad, are obscured by drift. 



Along the Ca7'riage-road in the Notch, etc. The beginning of the 

 original Notch, before railroad excavations cut into it, appears in the 

 heliotype opposite p. 79, Vol. I. The rock is the same with that de- 

 VOL. II. 22 



