52 KEMP'S ORE DEPOSITS. 



III. Cave deposits. \ Forms chiefly due to pre- 



IV. Gash veins. v existing open cavities 

 V. Fissure veins. ) or fissures. 



VI. Surface deposits. 



(a) Residuary deposits. 



(b) Stream deposits. 



(c) Lake or bog deposits. 



1.06.11. These three are all excellent, and give some interest- 

 ing variations in the several points of view from which each writer 

 regarded his subject. There are instances in the two German 

 schemes where it is difficult to render the original into a corre- 

 sponding English term and recourse has been had to the explana- 

 tory text. Grimm especially writes an obscure style. He divides 

 accordingly as the ore forms an essential and integral part of the 

 walls or a distinct body. Von Groddeck has in view the relative 

 time of formation as contrasted with the walls, Grimm afterward 

 emphasizes geometrical shape, but this Von Groddeck practically 

 does away with, and continues more consistently genetic. His 

 scheme might perhaps come more appropriately in the next section. 



Pumpelly's conception varies considerably from the others. He 

 writes, as his full paper states, in the belief that the metals have 

 all been derived primarily from the ocean, whence they have 

 passed into sedimentary, and, by fusion of sediments, into igne- 

 ous rocks. The group of residuary surface deposits, carrying out 

 as it does a favorite idea of Professor Pumpelly, as set forth in 

 his papers on the secular decay of rocks, is an important distinction. 



1.06.12. E. Schemes Entirely J3ased on Origin. 



(16) 

 H. S. Munroe. Used in the Lectures on Mining in the School 



of Mines, Columbia College. 

 I. Of surface origin, beds. 



(a) Mechanical (action of moving water). 



1. Placers and beach deposits. 



(b) Chemical (deposited in still water). 



1. By evaporation (salt, gypsum, etc.). 



2. By precipitation (bog ores). 



3. Residual deposits from solution of lime- 



stone, etc. (hematites). 



(c) Organic. 



1. Vegetable (coal, etc.). 



