364 CENTRAL MINERAL REGION OF TEXAS. 



B. OTHER SIMILAR LOCALITIES. 



Broad belts of quartz occur in the same trend as at Barringer Hill, in many 

 parts of the Burnetan exposure west and east of that locality. 



East of Nigger Head Peak, a little southwest from High Point, in Burnet 

 County, on a branch of Clear Creek, there is an outcrop of quartz which may 

 be an extension of the Barringer dyke. 



The " pressed " feldspar characteristic of the latter belt is not evident, but 

 a granite, with peculiarly fine crystallizations of orthoclase and rare minerals, 

 intersects the white quartz in much the same manner. 



There are enormous quartz belts following, an equivalent trend in the 

 Babyhead District, especially in the western part on Wolf and Pecan creek 

 headwaters. Some of these may have similar feldspathic associations. The 

 graphic granites and their allies — the complex feldspars — seem from present 

 knowledge to have an important relation to the occurrence of the rare 

 minerals in such situations, but we do not yet clearly understand the real 

 nature of this influence. 



In the westward continuation of the strike of the Burnetan rocks from 

 Barringer Hill, wherever good exposures can be found, there is reason, I 

 now think, for expecting similar results from careful prospecting. It is 

 wrong, however, to hope to make a business success out of any but the most 

 systematic mining of such deposits. The work done at the Colorado River 

 has been desultory, irregular, and without system. 



Other belts of the Burnetan quartz cross Llano County southward, and 

 parallel outcrops may possibly be opened in Llano and Gillespie counties, in 

 the bay of Archean rocks which runs southeast of Enchanted Rock towards 

 Blowout and Willow City. 



The belief in the relations of the feldspar and graphic granites to the 

 gnesses of the rare minerals is strengthened by the fact that prospecting thus 

 far has been unsuccessful in the quartz belts which are unaccompanied by 

 the irruptives aforementioned. 



VI. BUILDING MATERIALS. 



The Central Mineral Region is rich in rocks suitable for construction. 

 Some of them have been already proved in practical use in store houses and 

 dwellings, and others have much more than a local reputation. Many which 

 have not been so employed will, no doubt, become commercially valuable 

 when railroad transportation shall have made them accessible to markets. 

 As yet, however, there has been no systematic testing of any of the strata, 

 so that it is not possible to report in detail concerning the strength and dura- 

 bility of these natural products. Such facts as have been gathered are here 



