144 



<;i;ki:.\ mountains in Massachusetts. 



ceous matter which project on the weathered surface. (See Fig. 4(1). These 

 specimens clearly indicate infiltration and metamorphism subsequent to 

 cleavage. 



case v. 

 The stratification foliation and the cleavage foliation are both some- 

 times minute in the schist and equally dominant. Fig. 41 represents such 

 a specimen from Bald mountain on the west side of Grreylock. 





■' ili % ^ ^v •'- V Y* %N ' ' 



^ 



Fig. ii. Sp< i inn ii oi - hist from locality 95 on Maid inoun 

 tain, west side of Grey lock, not in natural position, showing 

 both stratification and cleavage foliations somewhat minute 

 and equally dominant. Each pair of opposite sides of the 

 block is parallel to one of the foliations, clea^ age dips to tbe 

 Ieft. From a photograph, 



Fig. 42.— Specimen of schist from local- 

 ity 621 north end of Mount Prospect, in 

 natural position, facing south showing 

 on'lj cleavage foliation, dipping 50° east. 



Fig. 42 represents ;i specimen from Mount Prospect in which only 

 cleavage planes dipping 50 c east are visible to the naked eye. Under a 

 magnifying glass the stratification foliation barely appeal's in minute crinkles 

 crossing the cleavage planes, but the cleavage foliation dominates. These 

 crinkles come out more clearly in an enlarged section (Fig. 43) and indicate 

 a westerly dip, which is confirmed by observations on some of the neigh- 

 boring ledges, where the stratification foliation, marked by small plicated 

 quartz lamina- visible to the unaided eye, dips at a high angle west. Simi- 



