1 68 STRATIGRAPHICAL GEOLOGY. 



and dip. This dyke may be five or six feet wide, and is supposed to cut 

 both the hard schists and the Breccia granite just below, towards Dismal 

 Pool. As seen from the carriage-road at its western curve, this James 

 ledge is full of reticulating granite veins, some two or three feet wide. 

 The strongest run north-westerly, but at three places one can see them 

 cut and shifted by smaller veins crossing nearly at right angles and other- 

 wise. With the sun shining upon their blanched surfaces, they are very 

 conspicuous. They also occur upon the hard ledges inside of the west- 

 erly projection of the road. 



Immediately below the cutting there is developed an extraordinary vein 

 or mass of granite, w^hose presence has led to the discovery of additional 

 interesting features in the geology of the Notch. The junction is now 

 concealed by the abutments just below the James cut, where it was dis- 

 played to the best advantage in fresh excavations. The phenomenon is, 

 briefly, a vein of slightly poi-phyritic (allied to the Albany) granite, 450 

 feet thick, dipping under the hard Montalban schists somewhat east of 

 north, the latter supposed to have a strike either N. 20° W., or N. 52° W. 

 As seen from below, the mass of schist has a slope of perhaps 15° from 

 the top of Mt. Willard to the James cut, underlaid by this bed of granite. 

 Both masses are cpiite conspicuous, and the line of junction, having the 

 direction N, 18° E., may be followed up past the flume, where the com- 

 mon strike of the schist is N. 27"" W., the dip being vertical. Near the 

 southern point of the schist the position is very nearly the same, the 

 strike being N. 22° W. At the head of the south or Butterwort flume, 

 the strike is N. 32° W. Hence the evidence is clear that this mass of 

 granite fills a chasm, passing scjuarely across the Montalban strata. Were 

 the granite a stratified formation, the relations of the two to each other 

 would be described as unconformable. The granite itself when fresh 

 shows a predominance of orthoclase in large crystals of half an inch or 

 so in length, and smaller rounded (sometimes crystalline) masses of 

 quartz scattered through a fine-grained granitic aggregate. The mica 

 may often be in black patches, large enough to be conspicuous, though 

 usually in very small bits. A finer grained variety of this rock occurs 

 near its junction, but is not abundant. As usually seen, this granite 

 has a reddish aspect from weathering ; and it has a close resemblance 

 to many ledges referred to the Albany series elsewhere among the 



