500 



Scientific Geology. 



Granite Vein in Mica Slate; Goshen. 



The mica slate in the northwest part of Norwich is frequently very 

 regular in its stratification, dipping west 80 : and this is the case 

 where No. 46 was sketched. A granite vein four inches wide crosses 

 the strata nearly at right angles, and the edges of the mica slate 

 show that the layers on opposite sides of the vein have been moved a 

 few inches laterally. The distinctness of the stratification enables us 

 to see this change more easily than is common. 



(46) Granite Vein in Mica Slate : Norwich. 



Nos. 47 and 48 represents granite veins in micaceous limestone in 

 the west part of Colrain. They are bowlders of about 2 feet in di- 

 ameter, and the veins only an inch or two wide. The extremely ser- 

 pentine course of these veins is the most remarkable circumstance 

 about them. For I could not discover any cause that makes them 

 thus serpentize. The limestone appears perfectly homogeneous 

 throughout, and is entirely destitute of any appearance of a laminar, 

 slaty, or stratified structure ; I mean so far as these specimens are 

 concerned. 



