570 CENTRAL MINERAL REGION OF TEXAS. 



Hundreds of thousands of dollars have been expended in Texas according 

 to the latter idea, as against comparatively small sums devoted to the former 

 mode of procedure, and the difference in the results is most strikingly ap- 

 parent in favor of the systematic method first mentioned. 



VII. If the preliminary investigation here advised does not show some evident 

 possibility of the existence of valuable materials, it will not be wise to undertake 

 any costly experiments; for the writer has neglected no opportunity for ex- 

 amining all parts of the region, and it is certain the chances for discovery are 

 stated here in as favorable a light as possible for every geologic terrane which 

 occurs in the district. 



PLAN OF PART II. 



For convenience of reference the substances which can be made available 

 in the arts and trades are classified according to their commercial uses in 

 the first place, with subdivisions based upon their mutual relations. The 

 metalliferous are first treated somewhat in the order of their intrinsic values, 

 after which the more important substances follow in an arrangement not 

 wholly arbitrary, but less with reference to a scientific classification than to 

 meet the wants of practical men engaged in commercial pursuits.* 



I. METALLIFEROUS DEPOSITS. 



The field work of this division of the Survey in 1890 has given us a view 

 of such parts of the region as were not covered by the explorations of the 

 previous year. Although much attention has been given by prospectors and 

 capitalists to the testing of deposits heretofore known, and the determination 

 of their geographic distribution, there has really been but little gain in actual 

 development of the metallic resources of the Central Mineral Tract. As 

 clearly explained in the report of 1889, the complexity of structure and the 

 greatly broken character of the strata make mining very disastrous pecuni- 

 arily, unless undertaken by thoroughly trained engineers who can properly 

 interpret the meaning of these numerous irregularities. The work done thus 

 far for the most part has not been of this systematic character, for which 

 reason it is still very difficult to arrive at just conclusions regarding the out- 



*A full discussion of the field from a scientific standpoint, illustrated by detail maps and 

 sections, was nearly completed for publication as Part III of this Report, but it has been found 

 necessary for the present to condense this matter into the few pages, which appear as the 

 Supplement, and to omit the illustrations. The value of the Report, even to those who care 

 only for the business aspects of our resources, is materially affected thereby, because very 

 much of the cost of working and of prospecting may be saved by the knowledge of the ge- 

 ologic structure which has been acquired by this Survey, and which only awaits publication 

 to become generally available. 



