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GEOLOGY A^Y> MINING INDUSTRY OF LEADVILLE. 



successor, Professor A. Serlo. The last, that of Dr. A. von Groddeck, of the 

 School of Mines at Clansthal, in the Hartz. 



Von Cotta's classification is founded exclusively on the form of the 

 deposit and recognizes no genetic principle as a basis of classification. Thus, 

 such essentially opposed deposits as coal beds and placer deposits, on the 

 one hand, and mineral veins and contact deposits, on the other, are ]iut 

 nnder one general heading ; while cave-fillings, pockets, etc., which may lie 

 merely offshoots from a vein or contact deposit, come under a distinct main 

 head. 



Grimm's classification is also mainly founded on the outward form of 

 the deposit, but he admits a few minor genetical distinctions, such as sep- 



