494 



Scientific Geology. 



(35) Granite Veins in Mica Slate ; Whately. 



No. 36 is situated near the same spot. It represents the inclined 

 surface of a ledge of mica slate, through which a granite vein of four 

 feet wide passes. This embraces three masses of mica slate of con- 

 siderable size, which are evidently separated entirely from the parent 

 rock, except one of them nearest the upper side of the sketch. The 

 layers of the mica slate, in the direction in which the granite was 

 erupted, are obviously considerably curved, as is shown in the figure. 



' 



Granite Vein in Mica Slate ; Whately. 



No. 37 represents a nearly perpendicular ledge of mica slate in 

 Conway, very much contorted, about two miles southwest of the cen- 

 ter of the town, a, a, are strata of common mica slate : b, is a stra- 

 tum of amphibolic mica slate. The whole surface exhibited is 15 

 feet long and eight feet high. Through this ledge runs a vein 

 of fine grained granite a foot wide. The object of giving the sketch 

 is to show that this vein has produced no derangement of the mica 

 slate : for the different varieties of that rock occupy the same relative 

 position on the different sides of the vein. Hence the vein was intro- 

 duced subsequently to the consolidation of the slate ; and probably it 



