GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 37 1 



the dip is 80° S. 62° E. For half a mile north of Hubbard's the slate 

 becomes micaceous, dipping 60° N. yj" W. A section of the rocks along 

 Sugar river is given farther on. The slate does not underlie the principal 

 village, though it touches its south-east extension, approaching the rail- 

 road station. The west line runs over the westerly slope of Bible hill, the 

 hill itself and the Flat Top near the village being composed of slate. 

 At a reservoir on the northern slope of Flat Top hill the strike is N. 27° 

 E., the strata being vertical or leaning slightly to the east. On the east 

 side the westerly dip is strongly marked. On top, the irregularities in 

 dip prevail, on the east side dipping 75 '^ N. W., and on the very apex 

 34°-50° S. E. On the summit of Bible hill, the highest part of the rock 

 mass of which Flat Top is the northern spur, the dip is about 85° S. E., 

 with north-westerly variations. In descending south-westerly, we observe 

 a large vein of white quartz. Near R. Cassady's there is a bed, ten feet 

 thick, of quartzite, full of minute undulations. Near N. Stone's house the 

 strike is north-east, and the dip is vertical. This house marks the west 

 edge of the formation. The mica schists adjacent dip towards the slate. 



I had occasion to examine Bible hill more carefully than usual, and 

 was impressed strongly by two classes of facts : First, the great diversity 

 in the position of the strata. As indicated above, north-westerly and 

 south-easterly dips are mixed together confusedly. It may be explained 

 by the second class, viz., the existence of numerous fissures of modern 

 origin, say post-glacial. I have never observed such fissures elsewhere 

 so abundant as here, either because attention was not specially directed 

 to them, or they do not exist. The fissures have probably been made 

 since the ice period, because the hill-top is covered by striae. Had the 

 cracks been as abundant when the glacier pummeled the hill, the ledge 

 could hardly have resisted its blows. It would have been carried away, 

 and the Sugar River valley been much widened. These fractures have 

 probably been caused by the lateral pressure, which shows itself often- 

 times in quarrying. When the strain is taken off by the removal of large 

 blocks, the tension will relieve itself by a spreading or moving of the 

 rock. 



To the south the slates diminish. They occur at North Charlestown, 

 on Calavant hill, with nodular masses of quartz thought to be auriferous. 

 A hornblendic rock — possibly gneiss — from the east point of this hill, 



