SERPENTINE, 243 



SERPENTINE. 



THERE is so little accurate information to be 

 obtained, from authors, respecting the geological 

 history of this rock, aiid the opportunities of 

 studying it in this country are so few, that I can- 

 not pretend to give much satisfactory information 

 respecting it. 



As far as has yet been ascertained, it occurs 

 almost exclusively among the primary rocks, 

 and is therefore properly placed in the present 

 division. It does not appear to be ever decidedly 

 stratified, or to alternate in such a manner with 

 the primary strata in which it lies as to give 

 ground for supposing that it is a stratified sub- 

 stance. It presents, at the same time, one strik- 

 ing difference from the unstratified rocks, which, 

 of whatever date they may be, are connected 

 with veins that branch from them into the sur- 

 rounding strata. No veins have yet been de- 



R2 



