MOUNT GEEYLOCK. 129 



the minor anticline on the west side of this part of the Hopper. The deep east to 

 west incisions (in both sides of the mountain are the results of erosion crossing the 

 strike, while the great spurs on the west side are portions of the original mass left 

 by this erosion. The saddle between Greylock summit and Saddle Ball seen from 

 the south (PI. xv) is due to the central syncline of the mass (Sections I and K). 

 The broader saddle seen from Mount Equinox on the north-northwest (Fig. 30, 

 p. 136) is due to the great trough in the central syncline (Section Q). The center of this 

 trough is the deepest part of the entire synclinoriuni. 



In Appendix A, Stone hill, near Williamstown, and in Appendix B, New Ashford, 

 are described m some detail. The former is accompanied by three transverse sec- 

 tions, S, T, CT, which are crossed by the longitudinal section R', from which itappears 

 that a subordinate syncline passes through Stone hill and Deer hill, whence it prob- 

 ably continues southward through East and Potter mountains. The relation between 

 Stone and Deer hills is analogous to that between Clarksburg mountain and < hey - 

 lock. 



MON XXIII 



