PRINCIPLES CONTROLLING ORE DEPOSITS 73 I 



extended paper found in Vol. XXX of the Transactions of the 

 Americaji Institute of Mining Engineers: 



There are three great classes of ore deposits; (i) those 

 which are produced by igneous processes; (2) those which are 

 produced by the direct processes of sedimentation; (3) those 

 which are produced by the work of underground water. The 

 last class is by far the largest, and it is the only one which I 

 shall consider this evening. 



My first, then, and my fundamental premise is, That the most 

 important class of ore deposits is the result of the work of underground 

 water. This premise I shall not attempt to prove ; but because 

 it is accepted by most geologists and by most mining engi- 

 neers shall use it as a starting point. 



My second fundamental premise is, Ore deposits are derived 

 from the outer crust of the earth, from that part of the crust of the 

 earth which I have called the zone of fracture. 1 - There has been 

 much discussion as to whether ore deposits are produced 

 by descending waters, lateral-moving waters, or ascending 

 waters. One of the most comprehensive papers which has 

 been presented upon this subject was by Posepny. 1 In this 

 paper Posepny holds that the original source of the metals of 

 practically all the ore deposits of the class produced by under- 

 ground water is the Barysphere (heavy-sphere), and there- 

 fore that the metals come from very far below the surface of 

 the earth. The water in some mysterious way came from this 

 heavy sphere, presumably very deep seated. The water rising 

 from the Barysphere, where the rocks are supposed by some to 

 contain more metalliferous material than near the surface, brought 

 the metals of the ore deposits to their present positions. This 

 view has. been presented at great length by Posepny, ably argued, 

 and he has had many disciples. Now it seems to me that the 

 well-established principles of physics absolutely disprove this 



1 Principles of North American pre-Cambrian Geology, by C. R. Van Hise : Six- 

 teenth Ann. Rept. U. S. Geol. Surv., 1894-5, Pt - 1> P- 589. 



2 The Genesis of the Ore Deposits, by F. Posepny : Trans. Am. Inst. Min. 

 Engineers, Vol. XXIII, 1894, PP« l 91-2>^>9- 



