332 CENTRAL MINERAL REGION OF TEXAS. 



vorable Perhaps the worst of all places to search, for gold is in the veins of 

 red and yellow oxides which occur in faults in the Silurian limestones, as on 

 Hinton Creek, Bluff Creek and at Camp San Saba and elsewhere. These 

 iron deposits have been thoroughly tested, and they contain no other metal. 

 Similar veins in the schists and gneisses, as near Long Mountain, sometimes 

 have rare metals in the matrix, but gold is not known to exist there. 



It is true that all possible chances have not been weighed by the Geological 

 Survey, but the whole matter will be most thoroughly investigated before 

 the subject is dropped, and if the final result be any different from this pre- 

 liminary verdict it will not escape the attention of the writer. 



2. SILVER. 



It is very difficult to arrive at anything like a satisfactory conclusion re- 

 garding the probabilities of silver -mining. As is shown in Table I, seven- 

 teen of our assays give traces and six samples have yielded from three ounces 

 to 107.8 ounces of silver to the ton. Without exception, the real returns 

 are from ores of the Babyhead District, including the area from the head of 

 Little Llano Creek westward to the head of Pecan Creek. This fact enables 

 us to form some idea of the best conditions in our region for the accumula- 

 tion of silver ores. The Babyhead District is one of the tracts in which the 

 Burnetan and Femandan strata (Archaean) are best exposed, and in addition 

 to this, the greater part has apparentty not been greatly disturbed by more 

 recent upheavals. This, it would seem, has left the fissures permanently 

 continuous, and accordingly there has been a much more uniform infiltration 

 than in other sections, where successive disturbances have obliterated possi- 

 ble prior accumulations and closed the channels of deposition. If this idea 

 be correct, we shall find areas of like character the best places in which to 

 prospect for similar ores. There are few such tracts, however, within the ter- 

 ritory now uncovered by the Paleozoic rocks. This little district is almost 

 unparalleled even in this region of unique structures. The nearest approach 

 to it is, perhaps, in an irregular area with Bodie Peak and Fly Gap as mark- 

 ers, although limited patches extending along the drainage of Big Sandy 

 Creek for the most part maybe other examples. The "traces" given in 

 assays recorded in Table I are mostly from exposures more or less closely 

 connected with the last mentioned district. It is noteworthy that traces of 

 lead are present in nearly all the samples from that tract.* We are not yet 

 prepared to speak understandingly of the special causes which have produced 

 the silver ores, nor of the source of the material of the veins. Enough tests 



*AH the material marked (J) in the tables was collected by Mr. G-. Jermy, and I have no 

 notes concerning the mode of occurrence or other features, although I have worked to some 

 extent over the same field in a small part of Gillespie County. 



