197 



CHAP. XXXII. 



Serpentine. 



THIS rock has never been duly studied by those who 

 have had opportunities of examining it widely, and 

 thence it has continued to be one of the difficulties of 

 Geologists. If my own views of its nature are derived 

 from Britain, they are founded, as on all other occa- 

 sions, on those essential facts and analogies which seem 

 to constitute the laws, or the philosophy of Geology ; 

 and thence, even this limited field of observation should 

 give the truth, as I trust it has done, in every other 

 case, where the same proceeding has been followed* 

 tinder a careful induction of essential facts, derived 

 from the same narrow but rich field. And hence, in 

 this case, as in all others, when I have borrowed from 

 authors, it has been under rigid care, arising from the 

 conviction that Nature cannot contain opposing truths. 



Serpentine occurs as a stratified, an unstratified, and 

 a venous rock; and thence it might have stood in 

 either of the two first great divisions. If I have here 

 vacillated, in changing its place to the former, having 

 included it among the unstratified in the Classifica- 

 tion of Rocks, Geologists may determine as it pleases 

 them, respecting a rock which occupies this double 

 place, though, in both, of igneous characters, and thus 

 bearing an affinity both to granite and gneiss. Thus 

 also have I placed it in the primary class, though oc- 

 curring, like siliceous schists and others, in both. 



It is difficult to ascertain, from foreign authors, 

 under what precise distribution most of the well-known 

 masses of serpentine on the Continent of Europe 

 exist; as geological language has not always been very 

 definite respecting stratification, and as, on that ques- 



