RARE MINERALS AND PRECIOUS STONES. 361 



rich in metallic iron and free from undesirable contamination. The distribution of the hy- 

 drated ores is practically unrestricted. "Workable deposits exist in connection with the 

 widest variety of rocks, from the oldest to the most recent, but the accumulations are chiefly 

 vein deposits and segregations, instead of bog formations. Hematites occur in various forms, 

 both as beds and as inclosures in quartz and other matrices. The magnetites form a well- 

 marked belt extending across the whole area along certain lines of greatest disturbance. 



"Without attempting a minute classification, and excluding some notable exceptions, it may 

 be stated in a general way that the magnetic ores follow mainly the trend of the oldest gneisses 

 and schists ; that the hematites, excepting those of secondary origin, are largely characteristic 

 of the Lower Potsdam and earlier horizons, and that the hydrated ores are in largest measure 

 direct or indirect alterations of the anhydrous deposits previously defined. As to geographic 

 distribution, although strict accuracy must be disclaimed at present, it is roughly correct to 

 designate the northwest trend and the region in Llano County (with extensions in Blanco 

 and San Saba counties) as pre-eminently the magnetite belt. The hematite belt par excel- 

 lence covers a wide area, bearing more nearly north and south, extending through a very 

 large share of Llano and Mason counties, continuing into Gillespie County. The more recent 

 cross trends carry in their strikes as a rule only the secondary deposits of magnetites and 

 hematite crystals and limonites. 



Speaking as a metallurgist, it is incumbent upon me to put forth cautionary 

 words against an error which has often blighted the prospects of rich iron re- 

 gions. While Llano County, and portions of the adjoining counties of Mason 

 and Gillespie, and perhaps limited portions of San Saba and McCulloch counties, 

 are certainly destined to become extensive producers of iron ores, the erection 

 of smelting plants is not now justified by the situation. Fuel is not abundant 

 in the area, excepting in a portion of McCulloch County, and it has been the 

 rule in metallurgic practice to ship ore to the fuel and not the fuel to the ore. 

 The reasons for this are obvious. I am not now saying that iron smelting 

 cannot and will not be eventually a success in the district where the ores are 

 produced, but anyone who is competent to form a practical judgment in such 

 matters must quickly discern the fact that the Central Mineral Region occu- 

 pies a position, commercially as well as geologically, equivalent to that of the 

 Lake Superior region, without the timber supplies of that area. That has 

 been emphatically a mining district, not a smelting centre. With all the 

 bright prospects of our region, it is to be hoped that capital will not be wasted 

 in the attempt to "build bricks without straw." Railroads for transportation 

 are much needed, and the building of these, with the opening of new coal 

 fields, or the development of those already known, will be the first wise step 

 in the creating of a profitable industry here. 



V. RARE MINERALS AND PRECIOUS STONES. 



The Archaean rocks and the porphyry veins and the intersections of the 

 folds of different ages afford numerous favorable situations for the formation 

 of uncommon minerals and what are ordinarily known as precious stones, 



