IKON. 615 



to the crossing of Miller Creek. Northward between Lone Grove and Lock- 

 hart Mountain, and southward from Lone Grove as far as Miller Creek, the 

 carbonaceous and calcareous strata have not been eroded from above the ore 

 beds, and still farther southward the later granitic masses have largely obliter- 

 ated the original structure. These geologic features are not as favorable to eco- 

 nomic mining as the conditions prevalent north of Lockhart Mountain, because 

 the ore can not always be found at the surface in the former areas. But the 

 exposures in the Babyhead Mountains are partly due to faults, and it is not 

 improbable that limited districts elsewhere in the belt may also present con- 

 ditions suitable for working. 



However, it must be remembered that this field is one in which the Bur- 

 netian system is prominent, and a portion of it is covered by Texian strata. 

 This means that denudation or lack of deposition over much of the belt has 

 left no chance for discovery of any of the Fernandian rocks, or of their thin 

 edges only. The magnetite beds themselves are not here so thick nor so 

 prominent as in some other districts. There is some evidence that this is 

 due to subsequent denudation and not to discrepancy in original deposition, 

 for it is a fact that the comminuted ores of later date are more abundant 

 along the path of this and adjoining magnetite bands. Analysis No. 1 re- 

 ported in Table III is of a sample of the Babyhead ore, perhaps somewhat be- 

 low the average product. Specimens of lodestone have been taken from this 

 band near Babyhead by Mr. E. T. Dumble, State Geologist. The line of out- 

 crop appears upon the Hensley league, survey No. 410, Llano County, but it 

 is there somewhat obscured by the overlying marbles, and it is also in part 

 converted into a hydrated ore (No. 47, Table III). 



THE TWO LLANO BANDS. 



There is an area about five miles in width between Packsaddle Mountain 

 and the Riley Mountains in which the Fernandian rocks are well exposed 

 wherever they are not cut out by later uplifts. This belt extends northwest- 

 ward to the Carabro-Silurian escarpment a little north of the south line of San 

 Saba County. The rocks are folded here as in the areas upon both sides, and 

 several times the succession of the strata is repeated. In all the exposures 

 the typical Fernandian section is exhibited, and there is usually some indi- 

 cation of the presence of iron ores in situations which correspond to the hori- 

 zon of the Iron Mountain Series. The marbles and graphitic schists cross 

 the Brady road between Pecan Creek and Valley Spring in two places, and 

 ores of value have been detected in a number of places among these outcrops. 



