616 CENTRAL MINERAL REGION OF TEXAS. 



Near the mouth of Public Pen Creek, northeast of the Cat Mountains,* be- 

 tween the two roads from Lone Grove leading to Valley Spring and Llano 

 respectively, I have seen good altered surface indications of the magnetite, 

 and such also appear in Public Pen Creek not far northwestward, and again 

 in the upper valley of Willow Creek. In the same course, south westward, 

 this band crosses the Llano River near the lower ford at Llano, where it ex- 

 hibits similar features,! and similar outcrops are repeated near the upper ford 

 one mile above Llano, but in both these cases the marbles prevail, indicating 

 that the hard ores lie beneath. 



In all the outcrops of these two Llano bands, which are broken at intervals 

 by faults and granitic irruptions, the magnetite seems to lie at a considerable 

 depth below the surface, and its altered products often appear now as hema- 

 tite or limonite. Neither of the bands has been prospected extensively, be- 

 cause the hard ores are not plainly visible at the surface, but there is every 

 reason to believe that they exist beneath at the proper horizon, and that they 

 may be eventually mined with profit. Numerous observations have been 

 made which confirm my judgment that the magnetite horizon is a persistent 

 one in the Fernandian System. 



THE IRON MOUNTAIN BAND. 



There are several localities in this course at which the development of the 

 magnetite deposits has been undertaken with some degree of enterprise, and 

 in which very large and valuable masses of this mineral have been exposed. 

 This belt is most persistent and can be traced for many miles. It has been 

 worked in Llano County at Iron Mountain and at points southwest of Llano, 

 while fragments of ore have been collected from the tracts at the southeast- 

 ern base of the Riley Mountains, where the quantity of derived segregations 

 on the surface is also enormous. In all good exposures, or wherever the ore 

 body has been tapped along the course as indicated upon the Economic Map, 

 between the Cambrian escarpment at the northwest and the similar cap at the 

 western edge of the Riley Mountains, the magnetite is invariably found to be 

 abundant and of the very best quality. And the same is true of the exposed 



*Name given on our maps to the hills locally known as Wolf Mountains, because there is 

 a Wolf Mountain on another Wolf Creek, also tributary to Pecan Creek, which is liable to 

 be confounded with them. For the same reason I have changed the name of the creek here 

 known as Wolf Creek to Cat Creek on my maps. 



f Slight changes in the geographic outlining of the more eastern Llano band are rendered 

 necessary by the plotting of our Survey. In last year's Report I referred a part of this 

 band incorrectly to another one which lies farther east. The Chaney diggings near Pack- 

 saddle Mountain do not belong to either of the two Llano bands. That band has been de, 

 scribed under the head of Manganese Ores, on page 605 of this Report, 



