C.S.A. Saltpetre Mine. Important to Texas in waging the Civil War. Site of natural deposits of bat guano, worked in the 1860s to obtain the chief ingredient for gunpowder. Cave inhabited by bats, source of the guano, extends about 23 miles. One room in the great bat den is 585' x 325', and has a 45' ceiling. A narrow gauge railway with mule drawn cars was used in the digging. Corrals for the mules occupied one chamber of the cave. Putrefied and dried bat guano, mixed with smaller parts of sulphur and charcoal, gave firepower to Civil War guns. 1965 #600