PRECIOUS METALS. 331 



often occur among the older rocks, but much less commonly in the later 

 trends. 



The assays made by Messrs. Herndon and Magnenat of material collected 

 by myself do not give much promise of profit. The material selected covers 

 the ground well, and it is hardly probable that extensive prospecting will 

 seriously alter conclusions based upon these samples, for they represent all the 

 types which have been detected in the whole region. 



In Table I these are shown in connection with the other assays. 



It is very probable, as occasionally reported, that higher specimen assays 

 have been obtained, and it would no doubt be possible for prospectors to dis- 

 cover rare pockets, and possibly some better indications than any here re- 

 ported, but the chances are all against the finding of any auriferous deposits 

 of workable size. The only mining operations which were systematically 

 carried on in the region in 1889, with gold as the object of search, consisted 

 of the sinking of a shaft on Silver Mine Creek, southeast of Enchanted Rock, 

 in Gillespie County. Here the thin streaks of ore, in contorted schists and 

 quartz seams, are chiefly very fine-grained, brassy pyrite, with some solid, 

 massive pyrite partly altered to hematite and limonite. There are also, at differ- 

 ent depths in the shaft, micaceous schists with spots of oxidized mineral, includ- 

 ing also some patches of quartz, pyrite being distributed meag;erly through the 

 mass. With these occur talcose and weakly graphitic pyritous schists. The 

 mechanical structure, or the crevices, preparatory to the occurrence of a min- 

 eral vein are here, but there has not been the regularity nor the subsequent 

 action necessary for the accumulation of such a deposit. The shaft, if con- 

 tinued in its present vertical course, will encounter different terranes and 

 different trends, perhaps, but it is likely to continue mainly in the Archaean. 

 There is a possibility that deeper working may strike similar schists to those 

 in the earlier trends in the Babyhead District, but gold would probably not be 

 abundant even in those. 



Thus far, the only district which has given us any returns in gold is the 

 area about the headwaters of Little Llano Creek and Babyhead Creek, in 

 Llano County. Here the gold is almost invariably associated with silver- 

 bearing or copper-bearing minerals, and it is therefore to be regarded as a 

 slight additional inducement to the mining of these metals, rather than as a 

 probable independent source of revenue. 



It has been claimed that the enormous alluvial deposits of Big Sandy 

 Creek contain enough gold to give respectable "colors" in the pan, but there 

 has not been any profitable working of these sands. 1 have occasionally 

 panned deposits of this character in different parts of the district without any 

 results of value, and as the quartz of the whole contributing area is mainly 

 barren, the prospects for future discovery of auriferous tracts is very unfa- 



