GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 405 



of ancient crystalline gneiss. Near the road the dip is 60° N. 52° W.; 

 forty rods north, it is 25° N.; fifty rods, 40° S. 50° E.; seventy rods, 45° 

 S. 58° E. Next to the conglomerate the gneiss dips 25° N. 70^ E. The 

 conglomerate dips N. 10° E., perhaps 50°. The pebbles consist of gneiss, 

 hornblendic gneiss, greenish quartzite, hard mica schist, compact feldspar, 

 and transparent quartz. Most of these are readily referable to the gneiss 

 near by for their origin. The greenish quartzites may have come from 

 the Huronian. The cement is feldspathic; but there is nothing, so far as 

 examined, that appears to have been derived from the Calciferous. Next 

 occurs felsite, in a variety of aspects. One is that of a dark, compact 

 variety, with whitish dots, showing pebbles only where it is weathered. 

 Another has a slightly trachytic aspect, of gray color, having crystalline 

 bunches scattered through a fine-grained paste sprinkled or peppered 

 with small black grains. Other portions have black hornblendic frag- 

 ments disseminated through them. Both these varieties contain crystal- 

 line bunches, having one mineral inside of another. I have specimens of 

 hornstone from this vicinity, but do not remember how abundant it may 

 be. Between the two peaks the ledges are chiefiy common and horn- 

 blendic granites. There is a junction of granite with a ferruginous rock 

 at the summit of the more northern peak, the line of union running north 

 and south. In the road between the two Ascutneys the rock is mostly 

 sienitic. Following the lower edge of the sienite easterly, we find a nar- 

 row band of gneiss extending beyond the point where the west line of 

 the mica schist would naturally pass. I should judge this might extend 

 three quarters of a mile east of the natural boundary line. The gneiss 

 to the east and south of Little Ascutney dips to the east. The edge 

 between the sienite and gneiss is quite irregular on the north and west 

 sides. 



The union of the sienite of the larger mountain with the calcareous 

 rocks is full of interest. The phenomena clearly establish the fact that 

 the limestones change their character in approaching the sienite, and 

 that their strike is not affected essentially. The strata dip at a very 

 high angle to the east, and cease abruptly on reaching the granitic rock. 

 It follows, that the granitic rock has been protruded through a fissure in 

 the Calciferous mica schist, and the accompanying heat and other agen- 

 cies have indurated the limestones, perhaps inducing in them the forma- 



