IN THE UPPER KIO GKANDE EMBAYMENT IN TEXAS. 101 



Third foot below surface 1 



Fourth foot below surface less than 1 



Fifth foot below surface less than 1 



Sixth foot below surface practically absent. 



From these figures it appears that some thirty or forty tons 

 of crude saltpeter might be extracted from the deposit in this 

 cave. A part of the richest upper crust has been I'emoved, and 

 this would reduce the quantity hj several tons. At all events 

 twenty tons crude saltpeter, probably containing ten percent of 

 salt, appears to be a fair estimate of the (juantity remaining. It 

 would have to be hauled about eigtheen miles over a bad road to 

 the nearest marketing place. 



This cave is located under an overhanging cliff of limestone 

 on the north side of a creek emptying into Devil's river from the 

 west. The cave is about five-eighths of a mile north from the 

 mouth of Indian creek. A small spring issues from the bottom of 

 the creek immediately below the cave. Implements of flint and 

 other rock, such as arrow-points and fragments of metates (small 

 hand-mills) occur throughout in the debris containing the salt- 

 peter. These relics, as well as the calcined stones, indicate the 

 origin of the debris. 



BAT GUANO. 



In the Devil's river limestone caverns are quite frequent. 

 These have been produced by the solvent action of underground 

 water, and thej are common in all limestone regions. Some of 

 these caves have for long periods been inhabited by bats, and con- 

 tain considerable deposits of guano. At least two are known by 

 the stockmen on the lands of the company. One is said to be in 

 the hills on the west side of Devil's river on or near survey 16 in 

 block B., and was spoken of as a small cave. The other cave was 

 entered by the writer and examined. Its entrance is on the north 

 slope of a hill adjoining a branch of an arroyo which runs into 

 Devil's river from the east on survey ] 5, block D. There is a ver- 

 tical hole about thirtj'-flve feet deep and this leads into the main 

 chamber of the cave. This is a hundred feet long, fifteen feet wide, 

 and thirty feet high. The floor of the inner part of this cave is 

 covered by from two to four feet of porous and dry guano, which 

 settles deep under one's feet. There are about 60 tons of guano. 

 If this were to be marketed, it would have to be hauled twenty 



Library PuhLicaiions, 7. 



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