452 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



always more or less stained with iron. Actual pseudomorphs of carbonate 

 of lead after cubical crystals of galena have been found, a? have also small 

 crystals of pyromorphite and molybdenite. The galena, as a rule, contains 

 a proportionately larger amount of silver than the carbonate of lead, as 

 might naturally be expected, since, in the oxidization of galena by perco- 

 lating waters, silver is removed in the form of chloride and has frequently 

 been i-edeposited at some distance from its original position. In this way 

 the Lee group of mines evidently owe their ore entirely to the later miner- 

 alizing action, since they are pi-actically free from lead and consist of chert 

 and hi^hh- silicious red and yellow ochers, impregnated with chloride and 

 chloro-bromide of silver, without an}- lead The darker- colored sand car- 

 bonates are, as a rule, the richer; those found in the Amie mine, for instance 

 have a dark-blue or greenish tinge and carry 300 ounces of silver to the ton, 

 whereas the light-colored carbonates of the Morning Star mine only contain 

 from forty to fifty ounces to the ton. 



The extreme irregularity of the occurrence of the ore renders any 

 generalization extremely difficult. It may be stated, however, that here, as 

 in all the other hills, the rich ore is generally, though not invariably, found 

 along the upper portion of the ore body. The main bonanzas or ore bodies, 

 as will be seen by reference to the map, have a nearly east-and-west direc- 

 tion, parallel to the dike alreadj^ noticed. It will also be noticed that the 

 richest bodies have been found in comparative proximity to this dike and 

 to the northeast of it, the main rich body to the southwest of this dike being 

 that in the New Discovery, Little Chief, and Little Pittsburgh mines, oppo- 

 ite what seems to be a partial break in the continuity of the dike. The 

 influence of this dike on the deposition of ore has evidently been to 

 cause an interruption or stagnation in the ore currents, by which their con- 

 tents were precipitated more richly in a sort of eddy immediately adjoining- 

 it. On the northern portion of the hill no large ore bodies have been found 

 as yet, although the existence of a large body of iron has been proved in 

 which there are found small irregular pockets of ore. Exploration in this 

 direction has been comparatively neglected on account of the great inrush 

 of water wherever shafts have been sunk to the ore horizon. Erosion must 



