378 CENTRAL MINERAL REGION OF TEXAS. 



3. BAT GUANO. 

 The caves in the Silurian strata about the sources of Beaver Creek, in 

 Burnet County, are many of them enormously rich in bat guano. Some 

 general notes have been taken upon this locality, but a more detailed descrip- 

 tion is reserved for the Report of 1890. Mr. Charles Huppertz, who was sent 

 to this cave in February, 1890, makes the following brief statement: 



The bat cave in the northwest corner of Burnet County is worked by a Georgia company, 

 and I learn from the men at work there that about 157 tons of the material had been 

 shipped up to December 20, 1889. The shipments are made by wagon to Lampasas, Texas, 

 and from there by rail to Georgia and other parts of the United States. The cave is situ- 

 ated about eight miles from Bluffton, going north up Beaver Creek. Near Lacy Branch, a 

 tributary of Beaver Creek, about two miles north of Silver Mine Creek, there is a fault on 

 the west side of Beaver Creek, in a branch which is called "Bat Cave Hollow." Proceed- 

 ing from this point in a northwest direction for about two miles we reach the bat cave, on 

 top of a higher chert bed. The way from Beaver Creek to the cave is constantly ascending, 

 first over Silurian limestone for about one mile, when the chert formation appears. On the 

 top of a chert hill there is an opening of about ten feet in diameter, extending perpendicu- 

 larly downward for 30 feet, where at the north side of this opening there is an entrance to 

 the cave. The cave has not been measured, but I estimate its length from north to south 

 to be about 600 yards, with as much, if not more, space in the opposite direction. The top 

 of the cave, as well as its sides, is solid chert, such as occurs in all the chert beds in San 

 Saba and all the neighboring counties. The guano bed in the heart of the cave has been 

 burned, leaving the ashes at places 26 feet deep, and not less than 18 feet at others. The ash 

 is not brought up, and the supply of guano is taken from the surrounding portions and sides 

 of the cave. As I understand, there are some leaders to the cave that have not yet been 

 explored, there being plenty of material near the heart of the cave for all present require- 

 ments. Five men were employed in digging and bringing out the guano, by means of a rail 

 track, to the surface, where it is deposited upon a large platform erected for that purpose. 

 At the slope of the cave hill is a large everlasting spring, running into Beaver Creek, near 

 the falls of the creek, depositing on its way large quantities of calcareous tufa, covering the 

 limestone at points to a depth of ten feet. There are other springs near by coming up on 

 top of the limestone, which fact, I think, is evidence of extensive faults all through this sec- 

 tion, which are perhaps caused by the sudden upthrust of a granite mass through Beaver 

 Creek, just above the mass of Lacy Branch. Strike south 20 degrees west, dip above the 

 granite northeast, and below southeast. 



The writer of this report has not yet visited the locality, but a large sam- 

 ple of the guano sent in by Mr. Huppertz is of very good quality. Analyses 

 and other tests are under way, but are not yet far enough advanced to enable 

 a report in detail to be made before these pages go to press. 



