10 



JOSEPH H. PERRY 



are clearly brought out. A glance at this sheet is sufficient to 

 convince anyone that the folding of the schist accompanied, and 

 was due to, the intrusion of the granite; and the force of intru- 

 sion was exerted in a northerly direction. 



Closely connected with the folding is the jointing in this 

 schist, which is very noticeable in every part of the mountain, 

 but especially above the line of vegetation. Here the rock has 

 been broken into large blocks, perhaps 20-30 feet long by 10-15 

 feet thick and wide, and these are so placed in the mountain as 

 to make a series of steps, as is shown in the accompanying 

 illustration (Fig. 4). This picture was taken at about the 2, goo- 

 foot level, and on the western side of the mountain. Observa- 

 tions of the direction and slant or dip of these joint surfaces were 

 made up on the mountain where there was little or no vegeta- 

 tion, and on different sides ; and they are arranged in the table 

 below. While there are not so many observations as there 

 well might be, they make clear certain facts or relations. 



Side of Mountain and 

 Elevation 



South ridge, southeast of top, 



2,500 level 



Southwest of top, 2,850 level . . 



West of top, 2,800 level 



Northwest of top, 2,800 level. . 

 North 30° west of top, 2,800 



level 



North of top, 2,800 level 



West side of mountain, i,goo 



level . 



Northwest side in Marlboro 



trail, 2,200 level 



Northeast side, 2,200 level .... 

 Northeast side, 2,400 level .... 

 Northeast side, 2,500 level .... 

 Northeast side, 2,700 level .... 



sa 



^ c c 



M.: 



1. In nine marked by a *, out of the twelve, the direction 

 of joint I is approximately the same as the strike of the band- 

 ing; or where the banding departs by local folding from paral- 

 lelism with the side of the syncline, joint i is parallel to the 

 side of the syncline. 



2. The angle between the strike, or direction of joint i, and 



