HOOSAC MOUNTAIN. 81 



elsewhere. Both rocks have their structure vertical with the small folds, 

 pitching lo to 15° northerly. In Profile iv a , PL v, itself we get another 

 contact. From here for 2\ miles to Profile v, PL v, the black schist is con- 

 cealed; then outcrops occur with easterly dip; east and west contacts with 

 the gneiss are concealed. In the creek of Profile vii, PL v, we have along 

 series of outcrops of the schist with the easterly contact beautifully shown, 

 the westerly within a few feet. These schists are extremely crumpled, as 

 shown l>v the quartz lenses; these crumples pitch gently northerly. The 

 rock is very gametiferous near the eastern contact with the white gneiss; 

 in other places feldspathic. At the east contact we have the white gneiss 

 dipping 20° easterly; it is a white, tnuscovitic variety. The schist layers can 

 be seen within less than 4 feet of strata from the base of the gneiss, dipping 

 gently under it ; intervening ledges are covered by the water or soil. It 

 indicates perfect conformity, both series dipping east. After forming a 

 series of cascades over this schist the creek runs out on a level and we 

 find here the rock succeeded by outcrops of micaceous quartzite or fine 

 grained gneiss, with same strike (north 10° east) and dip 25° east; the dis- 

 tance covered from one rock to the other is 25 feet horizontally. 



For half a mile south from the upper contact of Profile vu, PL v, it 

 can be traced very closely with the same strike and gentle easterly dip, 

 the contact being found often within a few feet and the structure of the two 

 rocks being conformable. At a mile from this contact we come to Profile x, 

 PL v. Here the actual contact was again easily found in the rocky cliff, 

 both white gneiss and black gametiferous schist much crumpled, but with a 

 general easterly dip of 10 : to 15°. The strike is north 25° to 30° west 

 and the small crumples pitch northerly 10° to 15°. This inclination affects 

 the topography; Fig. 10, p. 43, represents this spur, in which the gentle 

 slope towards the left of the picture (north) is due to the pitch of the rocks. 

 The lower contact is not found here. In Profile vill, PI. V, we have this 

 schist again outcropping, but neither contact. 



A mile farther, on the north fork of Tophet creek, in a deep gorge, we 

 find line exposures of the schist, much crumpled, and at the head of the 

 gorge its contact with the overlying white gneiss, which here again con- 

 tains transitional layers of micaceous gneiss, Both strike north 111 west 



MON XXIII G 



