Metamorjohic Upper Devonian Rocks. 371 



conformity, makes the same folds with it all the way from 

 the State-line, south to the point where the main South Ver- 

 non-Bernardston road crosses the railroad, even swinging round 

 to a 1ST.-S. strike where the schists do. Beyond this point it 

 occupies a broad area stretching from the railroad across to the 

 Purple blind road, and is plainly separated from the schists 

 on the north by a curvilinear fault. Thence it continues in a 

 broad band southeastwardly, a long distance, and can be followed 

 in scattered outcrops across the sand plains into the town of Gill. 

 Beyond Dry Brook it seems to regain its conformity with the 

 schists. Across the narrow neck by which the West North- 

 field sands join those of Bernardston, the same quartzite 

 reappears in the northwest shoulder of Grass Hill, and is 

 apparently continuous under the sands with the larger area 

 west of the railroad. It dips under the hornblende rock 

 to the east. 



It is everywhere a fine grained light gray fissile quartzite, 

 with small fresh feldspar crystals porphyritically disseminated 

 in it, often quite abundantly. These reach l-2 ram in cross- 

 section, are often but not always striated. They are much 

 larger than the quartz grains and have often sharp crystalline 

 outlines. 



In the area south of the great fault at the Purple blind road, 

 and far west from here, it is marked by the abundance of the 

 grains of lavender quartz included in it, which appear to have 

 come from the Archaean gneiss of the Green Mountains. Mus- 

 covite, so abundant in the lower quartzite, is wholly wanting ; 

 rarely a small amount of biotite in fine scales, or, at one out- 

 crop, of hornblende in scattered needles appear. 



The dips of the rocks and of the slates below are so low, 

 and, with the strike, vary so rapidly and irregularly within nar- 

 row limits, that I am left in slight doubt as to the exact con- 

 formity of the two for any long distance. Going north or 

 south from the northern road over the range, along the line of 

 junction for two miles, no contact of the two could be found, 

 but in the whole distance they seem exactly conformable, and 

 to have shared all minor disturbances together ; for instance, 

 although the rocks are tilted so that they strike N. 65° E. and 

 dip 40° S.E., they have also been subjected to an E.-W. 

 thrust, as is seen on a large scale farther south, so that small 

 portions placed irregularly among the rest have a JNT.-S. strike, 

 which is shared by both the schists and the quartzite. 



The basal conglomerate often blackened by argillitic mate- 

 rial is a rock of very different habit from this fine grained 

 biotitic feldspathic quartzite ; but the description above given 

 of the passage of the beds across Yernon indicates that the 

 former passes into the other going eastward beneath the schists 



