8 JOSEPH H. PERRY 



the Geology of New Hampshire : "In structure it (Monadnock), 

 seems to be a double synclinal. Again, on p. 24, it is stated: 

 "Mt. Monadnock seems to be an isolated, contorted synclinal of 

 andalusite mica schist." The strike of the schist in the area east 

 of the mountain, in the eastern slope, and in the northeast half 

 of the ridge of the mountain, is between north and northeast, 

 with a dip to the west and northwest. In the southern half of 

 the ridge, as far north as an east-west line passing through the 

 more southerly of the two houses on the mountain road, the strike 

 is from north to almost east, with the dip to the northwest. In 

 the top and in the northwestern part of the mountain the strike is 



K_^-'-..'^. 





Sea 

 level 



■ I . "- Z" ^ ^^^^■'■i- V"^- *- 







^jMii£i:£^£^ 



r~x^ 



level 



Granite 



Schist 



Granite 



Fig. 



3. — Section through Monadnock. Horizontal scale g^aiTo 

 tjIfo ; made from Topographic Map of U. S. Geol. Surv. 



vertical scale 



to the northwest, with a dip to the northeast. In the extreme 

 western part of the area here included, the strike is east and 

 west north of the granite lobe with the dip varying from ver- 

 tical to 40 ° south ; and the strike is northeast on the north- 

 west side of the same lobe, with the dip vertical. In the central 

 part of the mountain mass, between the northeasterly and north- 

 westerly strikes, the strike swings from one to the other through 

 an east-west direction, with a dip of about 45° to the north. 



The meaning of this variation in the dip and strike is that the 

 schist in the northern two-thirds of this mountain mass has been 

 folded into a synclinal having a pitch of 45° to the north; and 

 the western limb of this synclinal is continued in an overturned 

 anticline, with pitch to the south, around the western granite lobe. 

 The axis of the syncline is marked, approximately by the course 

 of Mountain Brook down the northern slope. The highest point 

 of the mountain is not at the apex of the syncline, but is in the 



