498 



Scientific Geology. 



is about 40° northerly : but where a granite vein of 4 feet wide (b,) 

 protrudes in a nearly perpendicular direction, the strata of the slate 

 on fhe lower side of the vein, for the width of 8 inches, (a) are bent 

 so as to stand perpendicularly against the vein. On the upper side 

 of the vein, and immediately in contact with it, the slate is hidden by 

 soil: but it appears again a few feet distant, at c. This example was 

 brought to light by the quarrymen, and as it was sketched several 

 years ago, ere this they may have destroyed all traces of it. 



(42) Granite Vein in M. Slate ; Goshen. 



No. 43 represents a vein of granite, only 1-8 of an inch thick, trav- 

 ersing mica slate in Conway, one mile southwest of the congrega- 

 tional meeting house. Strictly speaking it is a bed : for it is inter- 

 laminated with the slate and conforms to its tortuosities. It is not 

 perhaps easy to conceive how such a vein could have been intruded 

 between the layers of the slate, on account of its extreme thinness. 

 Perhaps it ought rather to be regarded as one of the layers of the 

 slate, produced in the same manrler as the laminae of gneiss. 



(43) Granite Vein in Mica Slate ; Conway. 



No. 44 was sketched near the same spot. It represents the edge 

 of a thick stratum of mica slate, whose dip is 50° east : and whose la- 

 minae correspond in dip to the strata seams. Among these laminae 

 and running in nearly the same direction, are three narrow and quite 

 irregular granite veins, a seems to have been injected from below, 

 and has no apparent connection with b, which would seem to have 

 flowed in from above, c is a third very narrow vein only 1-4 of an 

 inch wide, which has no connection with the others. 



I have sketched this case, because it seems more favorable than any 



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