148 



GREEN MOUNTAINS IX MASSACHUSETTS. 



distances, dip at the same angle, but vary from 30° to 90°, while their gen- 

 eral dip ranges from 40° to 80°; and the stratification dip lies between those 

 extremes, 1 >eing pr< ibably higher than the cleavage dip. If it could be shown 



that such lamina' are infiltrations in 

 fissures following alternatelv either of 

 the foliations, those portions of the lam- 

 ina- which do not follow the cleavage 

 foliation would alone afford reliable in- 

 dications, but if their occasional paral- 

 lelism to the cleavage foliation repre- 

 sents parts of the course of the stratifi- 

 cation their general dip should be taken. 

 At locality 207, near the junction 

 of Gulf brook and Ashford brook, there 

 is a large ledge of schist which shows very finely the relations of these pli- 

 cated thick quartz bands to both the stratification and cleavage foliations. 

 Fig. 48 represents the south side of the ledge. The minute plications 

 (stratification) of the schist and of the thin quartz laminae are generalized 



Fig. 47.— Quartz lamina? in relation I 

 schist, from locality 1-0. south of Deer bill 



I I'- 18. South Bide of s. hist ledge, locality 207. junction of Gulf anil Ashford brooks, showing the relation ..t i he 

 general .lip.il' the quartz lamina to the minute plications. This dip is 60° to 70°. The cleavage foliation, which includes 

 a thick quartz lamina below, dips 35°. Area Usui feet. From a photograph. 



in the broader undulations of the thick quartz lamina' which have an aver- 

 age dip of 60° to 70°. There is also a well-marked cleavage foliation 

 dipping 35 c in about the same direction. The cleavage planes do not 



