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GEOLOGY OF THE EDWARDS PLATEAU AND 11,10 GRANDE PLAIN ADJACENT TO AUSTIN AND SAN ANTONIO, TEXAS. By ROBERT T. HILL and T. WAYLAND VAUGHAN.
INTRODUCTION
The artesian systems of the eastern half of Texas are numerous and underlie several large areas. The productive areas extend from near Red River,Denton County,to Del Rio,on the Rio Grande, and from near the center of the State to the coastal islands of the Gulf. Collectively they comprise a district 450 miles in length and averaging 300 miles in width. It is doubtful if there has been anywhere a more remarkable development of artesian wells in the last tell years than in this region. At numerous places copious flows of water have been obtained, and districts which a few years ago had only inadequate supplies now possess artesian wells furnishing water in large quantities to cities,ranches, and farms,improving the hygienic conditions, and yielding water for the stock raising,agricultural,manufacturing, and transportation industries
The artesian wells of the eastern half of Texas belong to several distinct systems, the terns "system" including all wells having their source in the same set of rock sheets or strata. It would require a large volume to describe each of these various artesian systems. In the Cretaceous formations alone there are no fewer than five, and two of these the Travis Peak, or Waco, and the Edwards receive consideration in this paper. It is especially proposed to explain as well as possible the principles of the supply of the artesian belt supplied by the Edwards system and the probability of success or failure of wells sunk in different parts of its area.
Within the last two decades numerous artesian wells have been drilled in the vicinity of San Antonio, Texas, and for many years the source of the water has been a matter of perplexity. Unfortunately it has not been within our power to secure accurate logs of these wells, accompanied by specimens, or even to ascertain with accuracy the number and location of the wells, or to collect other essential data of a statistical "
The terms "Travis Peak" and "Edwards" are formation names used in this paper in place of "Trinity Sands" and "Caprina limestone," hitherto employed. The reasons for the employment of these new names are given on later pages (pp. 216, 227).