IRON ORES. 349 



streams, are usually not of this class. To test the matter, dig down to bed rock 

 only, and do not waste labor in excavating rocks which you do not know. Pay out 

 money for competent advice and act upon it. If you or your friends or " practical 

 miners" "have never seen such rocks before" experienced engineers can tell you their 

 values accurately by their tests. 



3. A body of magnetite ore having been found, it may be followed by the 

 dipping needle or by prospecting in a northwest or southeast direction. But 

 when you strike the red sandstone or other rock overlying, the beds with the northwest 

 strike will disappear beneath the others. 



4. Beds trending nearly north-south resemble these somewhat, but they 

 are of later date and the magnetic ores occur beneath them. You can rarely 

 find the ore bodies by digging in such places unless you have an intimate knowledge 

 of the geology of the country. 



5. There are at least three parallel belts in which it is possible that valu- 

 able deposits of 'magnetite may be discovered. 



A. THE BABYHEAD BELT. 



The most eastern outcrops follow a course represented by a line bearing 

 southeastward, west of Babyhead Postomce and Lone Grove, and coming out 

 southward very near the Wolf crossing of the Colorado River. This belt is 

 well exposed in the Babyhead Mountains, but is buried beneath the Cambrian 

 strata before reaching the north line of Llano County, which is thus practi- 

 cally the northern limit. The typical strike of the Fernandan System can be 

 traced southeastward nearly to the Colorado River, with some breaks where 

 more recent uplifts or alluvial deposits have cut out or obscured its path; but 

 no workable outcrops of the ore have attracted attention except those in the 

 vicinity of Babyhead. There is every reason to expect good results from 

 prospecting in the tract here outlined, especially in the north half, down to 

 the crossing of Miller Creek. Northward between Lone Grove and Lockhart 

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

 bonaceous and calcareous strata have not been eroded from above the ore beds, 

 and still farther southward the later granitic masses have largely obliterated the 

 original structure. These geologic features are not as favorable to economic 

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

 ore cannot always be found at the surface in the former areas. But the ex- 

 posures in the Babyhead Mountains are partly due to faults, and it is not im- 

 probable that limited districts elsewhere in the belt may present conditions 

 suitable for working. 



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

 netan System is prominent. This means that denudation or lack of deposi- 

 tion over much of the belt has left no chance for discovery of any of the Fer- 



