568 CENTRAL MINERAL REGION OF TEXAS. 



lining the cavities, and among these are several typical kinds. Fossils are 

 preserved in the last mentioned in many cases, but usually this material oc- 

 curs as fragmentary "float." Although very interesting geologically, no 

 present commercial use is known for the rocks of the Deep Creek division. 

 They are especially prominent along the lower reaches of Deep Creek, and 

 southward over a considerable portion of San Saba County; also forming the 

 hills east of Cold Creek, Llano County, north of the Burnet and Brady road. 



6. DEVONIAN SYSTEM. 



An inner fringe of rocks, mostly black or dark dolomites, some of which 

 weather yellow to red brown, with minutely honey combed texture, have been 

 provisionally referred by the writer to the Devonian, but this designation may 

 not hold after the fossils have been examined by the specialist who now has 

 them in hand. If not Devonian, they are probably Carboniferous. The areas 

 in which they are exposed are not extensive, and they possess no economic 

 value so far as known. 



7. CARBONIFEROUS SYSTEM. 



Some patches of Carboniferous rocks occur along the outer edge of our 

 district, and a vast area skirts it upon the north. An isolated patch forms a 

 part of Honey Creek Cove, in the Riley Mountains, Llano County. Aside 

 from the very thin and unimportant seam of coal which is occasionally visible 

 in sections south of the Colorado River, there is nothing of special economic 

 value except some fair building stones for local service. 



