600 CENTRAL MINERAL REGION OF TEXAS. 



Silica, abundant. 



Potassium, small amount. 



Sodium, trace. 



Tungsten, trace. 



Titanium, and probably tantalum and niobium, present together in large 

 amounts. 



In the precipitate containing sulphides and hydroxides of the metals of the 

 third and fourth groups of Fresenius (thrown down after the application of 

 ammonium chloride, ammonia, and ammonium sulphide), the part insoluble in 

 cold dilute hydrochloric acid was in' large proportion. This when dried was a 

 white powder, giving the reaction for titanium in the bead of phosphorus salt. 

 The colors and changes were very pronounced, but the blood-red color pro- 

 duced by the addition of ferrous sulphate, although evident, was much less in- 

 tense than the reactions which might be confounded with those of the metals 

 mentioned after titanium above. The insoluble residue, after fusion with 

 alkali, gave a strong reaction for niobium. 



Some of the partially fused fragments have minute adhering scales of a 

 rusty mica, usually with grains of quartz associated, a result which was very 

 possibly due to the use of schistose rocks from the vicinity as linings to the 

 furnace, although the glistening iron ore is itself occasionally slightly mica- 

 ceous. The fuel was probably charcoal, as old pits containing relics of this 

 material are still traceable in the neighborhood. The high specific gravity 

 and the imperfectly fused condition of the greater part of the slag, as well as 

 the remaining globules of tin in much of it, would lead to the inference that 

 the smelters had access to some deposit of cassitente in the region. This 

 may perhaps eventually be discovered, now that the geological conditions for 

 its occurrence have been shown by the writer to exist in a belt crossing near 

 this locality. The prominence of the metals of the shiny titanium ores in the 

 slaggy relics, and the evidences of early mining in the area of their occur- 

 rence in Shaft Mountain, render it almost certain that the furnace was used 

 for the reduction of those minerals in part. The other ingredients suggest 

 the admixture of f eld spathic minerals as an inferior flux, for it is certain that 

 no limestone nor ordinary fluxing ingredient (except perhaps ferric oxide) 

 could have been used in this instance. The shaft referred to was sunk in 

 orthoclase, carrying the ore described under b, page 597. 



