250 THE IRON ORE DISTRICT OF EAST TEXAS. 



No. 834. G-eodic crumbly iron ore, eight miles south of Timpson, Shelby County. 



No. 835. Concretionary iron ore, four miles south of Timpson, Shelby County. 



No. 836. Conglomerate iron ore, one-eighth mile south of Timpson, Sholb}^ County. 



No. 837. Iron sandstone, partly hematized, seven miles south of Timpson, Shelby County. 



SANDSTONE. 



About five and one-half miles north of Timpson is a little stream taking its 

 origin from springs which issue from the water bearing sand. Overlying this 

 sand is an extensive deposit (twenty-five feet) of soft sandstone, slightly im- 

 pregnated with iron, giving it generally a yellow color, except where the iron 

 was stronger and has stained it a reddish brown color. The water flowing 

 from the springs carries with it a considerable quantity of loose white sand, 

 and this has so undermined the soft sandstone that it has "caved," forming 

 an escarpment or bluff. The under part of the bed has gradually released a 

 portion of its material and thereby formed a hollow pit-like opening, from 

 which it has derived its name — Cave Spring. The sandstone is soft and fri- 

 able, and therefore not sufficiently strong for building purposes. 



The only other bed of sandstone observed in this county is on Wolf's 

 Mountain, eight miles south of Timpson, where the top layer is indurated, 

 partly from cementation, and thus protected a bench having now only a small 

 outcrop. This exposure shows a distinctly stracified condition, the lower 

 portion being cross-bedded. A second bench of softer material, also of small 

 extent, was protected by the overhanging upper ledge until it broke, and a 

 portion of it rolled as bowlders to a lower position on the hillside. See Fig. 

 19, p. 253. 



GLASS SAND. 



The only exposure of an extensive bed of soft white sand noted in this 

 county is that already described at Cave Spring, about five and one-half miles 

 north of Timpson, where a portion of it is stained yellow and red by the 

 trickling*of an iron solution from above. The thickness of the bed is about 

 twenty-five feet. In mining it for glass sand the stained portion could be 

 rejected. If the alumina be sufficient to become detrimental it could be 

 washed out, as there is sufficient water at hand for the purpose. Fuel is also 

 abundant in the neigborhood. 



There are probably other beds of white sand in this and other portions of 

 the county, at present covered by surface soil. 



