~5 "3 \ ^ 



PREFACE 



The principal object of this little work is to point out 

 the general order and uniformity of rocks, and the mode 

 in which minerals are disseminated and concentrated in 

 them. There is no branch where there is so much capi- 

 tal expended without any established principle to guide 

 us as mining — the opinion of a practical miner being 

 often the only inducement to carry on a mine ; and 

 when two practical men differ, there is no data at pre- 

 sent by which a third person can decide who is right. 

 Both persons may be governed by the indications ob- 

 served in their respective district, neither of w T hich may 

 be applicable to a mine in another locality. 



With the view of obtaining some well-founded prin- 

 ciple to guide us in our subterranean works, the Author, 

 during several years' professional engagement in this 

 pursuit, has paid very considerable attention to the sub- 

 ject, both in America and Europe : this brief sketch is the 

 result of his investigations. The principle here brought 



