102 A GEOLOGICAL SUKVEr OF LAJ^DS 



miles by wagon over a very bad road which crosses Devil's river 

 at an almost impassable ford. In all probability there are other 

 bat caves on these lands. 



CONCLUSION. 



The survey of these lands shows that the region has nowhere 

 been affected by those relatively more efficient volcanic agencies 

 of circulating moisture and of pressure and heat, which bring- 

 about the concentration of such minerals as gold, silver, copper, 

 or their ores, and the ores of lead, zinc, or quicksilver. The rocks 

 are but little changed from the condition in which they were orig- 

 inally deposited. Violent folding, crushing, or dislocation is 

 absent. Yolcanic products are only seen at a few places, and con- 

 sist of a few remnants of intrusives from extraneous sources. But 

 there are deposits of other minerals. They are of the kind whicli 

 occur in regions not greatly affected by metamorphic agencies. 

 Enumerated in the order of probable importance these are as 

 follows: 



1. Coal, certainly found on surveys 166, 19S, 199, block 7, 

 surveys 5, 4, 6, 7, block 16, and probably worth exploring for on 

 a belt extending several miles farther east. 



2. Gas, known to exist in valuable quantity on survey 116, 

 block 6, and indicated as more or less probable for scattered 

 points on an area of twenty-five square miles to the north and 

 west of this survey. 



3. Artesian water, indicated for some tracts north of Eagle 

 Pass on the Upson clays and partly known and also indicated on 

 some of the lands north from Carizzo Springs. Also indicated for 

 some of the land in Dimmitt county. 



4. 0/7, quite likeh'' to be found in association with the natural 

 gas. Possibly also may some time be distilled in commercial 

 quantities from certain black shales in the Eagle Ford formation 

 from Sycamore creek, northward and westward. 



5. Lignite, found in the region of greatest thickness of the 

 tertiary rocks, and existing in the west edge of the same forma- 

 tion, possibl^^ in valuable quaintitj' at some points. 



6. Cement material, found along the Southern Pacific rail- 

 road near Spofford, also at points from Sycamore ci'eek and west- 

 ward. 



