348 CENTRAL MINERAL REGION OF TEXAS. 



positions of the bright red soil belts which are successively crossed in going 

 from Lone Grove to Cold Creek, on the Burnet and Mason road, or in trav- 

 eling an equivalent stretch of country by almost any other route. It is also 

 a very interesting fact that the derived, or secondary, iron deposits of later 

 date, in the basal Cambrian strata at least, follow roughly the same trend, 

 though in a much less pronounced manner. 



The area in which the Fernandan beds prevail as surface rocks may be 

 limited for the present practical purposes by northwest-southeast lines, drawn 

 through Lone Grove Town upon the east and through Enchanted Rock upon 

 the west. This blocks out a district twenty miles wide and extending, per- 

 haps, thirty miles in the direction of the strike. Within this field, however, 

 various structural features have prevented, in many places, the outcropping of 

 the iron-bearing system, so that probably two-thirds of the area is not in con- 

 dition to yield ore without removing thick deposits of later origin. Assum- 

 ing that one-third of the territory, in scattered patches, will show the Fer- 

 nandan Beds at surface or at depths that may be considered workable from 

 an economic standpoint, it must be understood that only a small fraction of 

 the thickness of these strata is iron ore. Keeping in mind also the folded 

 condition of the rocks, it is evident that the chances for mining will be de- 

 pendent largely upon the character of the erosion, it being premised that the 

 iron bed, if such it be, is not very near the top of the system to which it 

 belongs. 



It is the province of this Survey to obtain facts and to draw conclusions 

 concerning the general nature of the ore deposits, as dependent upon geologic 

 structure. It is not, as some have imagined, the business of the writer to 

 ascertain and inform every land owner of the value of his property or of its 

 mineral contents. But if any intelligent citizen will apply to individual cases 

 the generalizations in these pages where they fit, and if he will undertake to 

 study his own locality as a minor, but integral, part of one or other of the 

 districts outlined in our natural classifications, he will at least be able to deter- 

 mine whether he can hope to discover iron or other ore upon his land. 



The main facts and the conditions in which the magnetic ores are placed 

 are these: 



1. Whenever a set of rocks appears such as is described in Part I of this 

 Report under the head of Iron Mountain Series,* there is liable to be a valu- 

 able deposit of magnetite. In prospecting, he sure that you have a set of rocks 

 whose strike is very nearly northwest {magnetic). 



2. If, in the same connection, a large amount of red soil occur in com- 

 paratively narrow strips, there may be a good ore body at no great depth 

 beneath the decomposed portions. Wide belts, especially along valleys of 



*See page 2*71 of this volume. 



