484 



Scientific Geology. 



No. 16 exhibits a mass of granite three rods wide, with mica slate 

 on each side, and embracing strips of mica slate from one half inch 

 to six or eight inches wide. The direction of the layers in these in- 

 sulated strips corresponds w 7 ith that of the mica slate generally in 

 the vicinity : viz. a north and south direction. This case occurs in 

 Chesterfield, one mile east of the meeting house, on the road to 

 Northampton. It is easy to explain it on the supposition that the 

 granite was erupted from beneath in a melted state : but I find it hard 

 to conceive how such effects could have resulted from aqueous agency. 



(16) Mica Slate in Granite : Chesterfield. 



The sketch below represents a nearly perpendicular ledge of gneiss, 

 from 70 to 100 feet high, in the lower part of which amass of granite 

 appears, which does not rise through the strata. The gneiss has a 

 small dip to the west, though somewhat irregular. The vein of gran- 

 ite is irom 10 to 12 feet thick, and rises thirty feet. The locality is on 

 the north side of Housatonic river, near Southbury, Ct. close by 

 what is called Zoar Bridge. 



