584 CENTRAL MINERAL REGION OF TEXAS. 



narily, and which may perhaps be of sufficient value to work as simple lead 

 ores. In writing of these accumulations in the last Report I remarked:* 



Of these trends only one has shown good warrant for the hopes of its advocates, although 

 it would seem that this can not monopolize the essential conditions, for there are other very 

 similar exposures. * * * It is very probable that systematic exploration in this region 

 may result in the discovery of large and valuable deposits of galena, for the rocks, the mode 

 of occurrence, and t]^ geologic age of the ore beds correspond generally with the conditions 

 existing in Missouri, Illinois, and "Wisconsin where lead has been extensively produced. 

 * * * It may be many years before the usual process of discovery will determine the 

 value or lack of value of the district, but comparatively little well directed effort under com- 

 petent guidance would soon settle the question whether lead bonanzas exist in cavities in 

 the limestone. As preliminary this Survey will undertake to determine the coming season, 

 if possible, the geologic relations of the strata in which the lead has already been found. 



The field work of this division in 1890 has enabled me to speak with more 

 definiteness concerning the conditions which prevail in the localities previously 

 announced, and to report some new discoveries which agree in all essential 

 points of structure. The possibility is that only a small part of the deposits 

 of galena has yet been brought to light, for the conditions which prevail in 

 the known localities are not unique There are many places where explora- 

 tions might be conducted with at least a moderately fair chance of discovery, 

 but it is necessary to pursue such investigations with a clear understanding 

 of the situation in the productive areas. This maybe better gained from the 

 following descriptions and illustrations. 



In a region so imperfectly worked as this there is an impropriety in attempt- 

 ing to lay out geographic or geologic areas which may even approximately 

 represent the lead bearing belts. Such allotment is particularly inapplicable 

 here on account of the broad extent of the rocks which may possibly be 

 charged with the ore. The classification of localities adopted is therefore to 

 be taken only as one of convenience for present purposes. 



THE BURNET COUNTY TRACT. 



The exact conditions of the substructure in the lead bearing area on Beaver 

 and Silver Mine creeks, in Burnet County, can not be made out in sufficient 

 detail to serve as a working guide until more mining has been done, or at 

 least until more time can be given to the study of the problems involved in 

 the situation. The cut (Fig. 65) exhibits, however, a geologic plan and section 

 which does not exaggerate the complexity, although it may not represent all 

 the details as they will eventually be worked out in the development of the 

 tract. 



*Op. cit, p. 340. 



