CHAPTER VI. 



THE CLASSIFICATION OF ORE DEPOSITS, A REVIEW AND A 

 SCHEME BASED ON ORIGIN. 



1.06.01. In the classification of ore deposits the same syste- 

 matic arrangement is not to be expected as in the grouping of plants, 

 animals, or minerals. Ore deposits have not the underlying affin- 

 ities and relationships of living organisms or of definite chemical 

 compounds. The series of objects is too diverse, and, in the na- 

 ture of the case, the standards of appeal must be different. The 

 subject is, however, one of great practical importance as well as 

 of great scientific interest. A vocabulary of intelligible terms is 

 indispensable for description and comparison, and, under our min- 

 ing laws, often for valid titles, while as a vehicle for the spread of 

 knowledge and reasonable conceptions regarding these phenomena, 

 its importance cannot be overestimated. 



1.06.02. All schemes of classification rest on these principles : 

 form, origin, or the genetic principle (including method, relative 

 time of origin as contrasted with the walls, etc.), state of aggre- 

 gation, and mineral contents. Of these, the principle of form is 

 usually esteemed the weightiest, and is given the greatest promi- 

 nence, partly because it has been thought to be the one most close- 

 ly affecting exploitation, and partly because it involves less that is 

 or has been, up to very recent times, more or less hypothetical. 

 Yet form is largely fortuitous, and it has, of course, no law, while, 

 with sufficient knowledge, the genetic principle is the one giving a 

 far more thoroughly scientific basis. Every one, in opening up or 

 searching for an ore body, must be influenced by some hypothesis, 

 either of shape or of origin. It is the conviction of the writer 

 that, with all our deficiencies of knowledge, the genetic principle 

 is also the best guide, even in practical development. 



1.06.03. Very early in the development of mining literature 

 the distinction was made between those ore bodies which are 

 parallel to the stratification and those which break unconformably 



