334 CENTRAL MINERAL REGION OF TEXAS. 



naces of simple type, besides a crude sluice for washing (concentrating) the 

 ore, and a small arrastre for grinding it. Assay No. 12, in Table I, is lead 

 matte from the reverberatory, and No. 10 is concentrated ore from the same 

 place. I have no means of knowing positively that the ore came from this 

 place, but it agrees well in character with what occurs in place in the neigh- 

 boring veins. 



The occurrence of silver ores, as stated, proves that the conditions for such 

 deposition were present in the Babyhead District, and it is not improbable 

 that other places of the kind may be found. But prospectors should give 

 most attention to localities in which these same conditions prevail. There are 

 no exposures elsewhere as favorably placed, although it may be that erosion 

 has uncovered similar limited areas. The next most promising fields, per- 

 haps, are the country east of Mason, in Mason County, and along the upper 

 valley of Comanche Creek, and the lower valley of Beaver Creek (Mason 

 County). Other suitable districts may possibly occur in Gillespie County and 

 northward on tributaries of the Big Sandy; but explorations have not thus 

 far been successful in that tract. 



The occurrence of galena in the Burnet County Beaver Creek District 

 opens a possibility for silver production there. As far as now known, there 

 is no probability of any occurrence of the precious metals in any other min- 

 eral in that area. 



Referring to assay No. 4, in Table I, for particulars, and to the title " Lead" 

 for a description of the environment, further mention here is unnecessary. 



II. BASE METALS. 



Under this head, for our purpose, we may class copper, lead, zinc, and tin, 

 these being the only metals of the group, excepting iron and manganese, which 

 present indications give any hope of discovering in the region. 



1. COPPER. 

 The district from which the greater part of the specimens of copper ore 

 have come is almost identical with the silver tract. The occurrence of copper, 

 however, is more extended than the known deposits of silver-bearing min- 

 erals. A cause o*f this may be, perhaps, the greater readiness of the copper 

 minerals to oxidize. This idea is, in a measure, supported by the fact that 

 such copper ores as are known outside of the silver vein courses are almost 

 wholly carbonates. Such as least has been my own experience with these 

 ores. The new element of distribution is the north-south trend, and appa- 

 rently a basic irruptive? of Post-Texan age is the exciting cause; for it is 

 where meridianal dykes of such material transect the Burnetan or Fernandan 

 trends that stains of malachite and azurile are found in the Texan rocks. The 



