140 



GEBEN MOUNTAINS IN MASSACHUSETTS. 



resulting in a coarse foliation crossing the stratification foliation at angles 

 varying from 45° to 90 ', and abutting against the limestone which under- 

 lies tlie schist in conformable contact. 



Fig. 34. —Thin section of a specimen from the upper part of the rock figured in Big. 32, locality 207, Quarry hill. New 

 Ashford, enlarged almost 'J diameters, showing cleavage planes arising in slight faults along the sides of the plications. 

 The fractures which occurred in the preparation of the slide are mainly in the direction of the stratification foliation, 

 which here dominates. 



cash; III. 



At the south end of Sugarloaf mountain, one of the subordinate folds 

 of the Greylock mass, a small isolated mass of feldspathic schist over- 

 lies the crystalline limestone. (See map, PI. i, locality 3'24 and Fig. 35.) 

 Here limestone and schist are seen in contact, both distinctly plicated, ami 



Fio. 35._Diagrammatir sketch of the south side ol a ledge at locality 324, south foot of Sugarloaf mountain, New Ash- 



ford, showing albitic schist in conformable contact with underlying crystalline linn-stone, ami a coarse and lii leavage 



foliation crossing the stratification fnliation »t' both rucks. 



dipping in a general westerly direction, but really forming part of a minor 

 fold. Where the stratification foliation dips 60° west it is crossed by 

 cleavage planes dipping 35° east, which in places traverse both rocks. 

 The limestone a few feet away from the schist appears in thick beds. Both 

 schist and limestone are traversed here and there by coarse or fine cleavage. 



