REPORT OF THE STATE GEOLOGIST. lix 



ful prospector will now know where to expect such ores, and also where 

 they can not exist. Connected directly with the three systems already 

 discussed, we find the copper ores, with their variable associations of 

 silver, and possibly a little gold, and the magnetic and other iron ores, 

 whose extent and richness will yet be one of the crowning glories of 

 the district. 



Gold. — The prospect for the finding of gold deposits in this region, 

 in quantities of any economic value, is very slight. It may, however, 

 be found in variable quantities associated with other ores. 

 , Silver. — Silver is found in the rocks of the Burnetan and Fernandan 

 systems with ores of lead and copper in veins ; and, while the bodies 

 of ore which have been found up the present are not large, the quality 

 of the ore is sufficient to warrant a more careful search under skilled 

 advice and with modern mining appliances. 



Copper. — These silver ores, as has been stated, are associated with 

 galena and copper. Very little of the galena belongs to these series, 

 but the copper ores are found principally in these rocks. Their pres- 

 ence is most plainly observed when rocks of the Burnetan and Fernan- 

 dan systems in their regular east- west course are crossed and broken by 

 the north and south rocks brought up by the Post-Texan uplifts. This 

 very fact complicates the vein formations, and renders a study of these 

 three systems and their accompanying eruptions an absolute necessity 

 for the proper economic working of these ores. 



The surface indications of copper ores are the green carbonates of 

 copper which appear so plainly in the rocks, and in a few cases even 

 grey and peacock copper have been found at the surface in stringers of 

 quartz. Analyses of the ores taken from different prospects show that 

 the quality is sufficiently rich to justify the thorough investigation of 

 the outcrops and the sinking of deep prospect shafts. 



Manganese. — Another very valuable ore of this group is that of 

 manganese, which occurs in the Fernandan trend, i. e., northwest- 

 southeast (magnetic). The value of this ore in steel making is very 

 considerable, and the indications are that other bodies similar to that at 

 the Spiller mine will be found when proper investigations are set oh 

 foot. The ores at the Spiller mine can be procured in quantity and 

 quality sufficient to make them marketable. 



Iron. — As has already been shown in the general section of the Fer- 

 nandan System, one of its most persistent strata is a bed of magnetic 

 iron ore. While it cannot be stated at present that there is one con- 



