File:Bulletin - United States National Museum (1967) (14761439796).jpg

Identifier: bulletinunitedst2591967unit (find matches)
Title: Bulletin - United States National Museum
Year: 1877 (1870s)
Authors: United States National Museum Smithsonian Institution United States. Dept. of the Interior
Subjects: Science
Publisher: Washington : Smithsonian Institution Press, (etc.) for sale by the Supt. of Docs., U.S. Govt Print. Off.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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per Plioceneor early Pleistocene stream levels at the eastern edge of the EdwardsPlateau, Barr (1960b) suggested that caves developed along theeastern margin of this plateau are no older than early Pleistocene.The origin of subterranean waters resmging through a number of largesprings along the Balcones fault zone between Austin and San Antoniois not fidly known. Sellards et al. (1932) pointed out that while many 242-803—67 10 140 U.S. NATIONAL MUSEUM BULLETIN 2 59 of these large springs exit thiough the Edwards limestone, much oftheir water may come from aquifers developed in the Trinity forma-tion. The Trinity group contains the cavernous Glen Rose limestonewhich crops out west of the Balcones fault zone and contains a numberof caves in Bandera, Kendall, Comal, and Bexar Counties. Originin Glen Rose limestone of some of the ground water which ultimatelyresurges along the Balcones fault zone would imply several ratherextensive subterranean drainage systems in this part of Texas, As
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MEXICO GULF OFMEXICO Figure 33.—Distribution of species of Stygonedes in central Texas. (The flagellatus group:A S. dejedus; A S. flagellatus; 9 S. longipes; * S. pecki. The hadenoecus group: 0 S.hadenoecus. The tenuis group: + S. halconis; X S. bifurcatus; Q S. reddelli; O S. rus-selli; n Stygonedes species. Two symbols in a circle indicate two species from samelocality.) Reddell (1964b) pointed out, how^ever, the relationship between thehydrologic systems and the development of caves in this region,especially in the vicinity of Comal County, is still poorly known. Theoccurrence of numerous and extensive faults further complicates thepicture. It is, then, perhaps significant that one of the four rare species ofthe flagellatus group, i.e., S. pecki, is known only from two specimenstaken from the cave-like exit of Comal Springs in New Braunfels,Tex. According to Reddell (1964b), this spring is the largest in thesouthwest and produces 210 million gallons of water per day. Col-lecting

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