REPORT OF THE STATE GEOLOGIST. lxxxiii 



The Upper Cross Timber or Trinity Sands. 



On the lower Rio Grande there occurs a sandstone known as the Car- 

 rizo Sandstone, the geologic age of which is not yet exactly determined, 

 but which must be included among the other water-bearing beds. 



That these belts are indeed catchment basins and fully capable of 

 supplying the belts nearer the Grulf with flowing water has been amply 

 verified by actual and successful boring. In the Coast Clay belt ar- 

 tesian water has been secured in many places, as at Houston and 

 vicinity, at Galveston, at Velasco, at Corpus Christi, and at various 

 other points. The shallowest of these wells is at Yorktown, De Witt 

 County, where artesian water was secured at a depth of a very few feet. 

 At Houston water is obtained in wells from one hundred and fifty to 

 four hundred feet deep, and the w T ater is practically free from mineral 

 matter. At Gralveston, fifty miles southeast, the wells are from six 

 hundred to ten hundred feet deep, and yield water carrying salt, etc., 

 in small quantities. The flow at Velasco is reported to be good, but 

 at Corpus Christi it is highly charged with mineral matter. The quan- 

 tity of mineral matter contaiued in the water seems to vary with the 

 depth and distance from the outcrop of the catchment basin. 



It can be stated, therefore, from our present knowledge that through- 

 out the Coast Clay district artesian water can be obtained where the 

 topographic conditions are suitable, but that it may be more or less 

 impregnated with mineral matter leached out of the containing stratum. 



While the Timber Belt Beds are not classed as artesian beds, it is 

 nevertheless the fact that favorable conditions exist in numerous local- 

 ities, and although no great flows have been secured, still flowing water 

 has been found in several places ; for example, various localities in Rob- 

 ertson County and at Livingston, Polk County. 



The Lower Cross Timbers form the second catchment basin, but from 

 their location have not been found to yield as good a flow as can be ob- 

 tained by going deeper to the Trinity Sands. 



The Carrizo sandstone outcrops along a line drawn at a point on the 

 Nueces River south of the town of Uvalde to a point ten miles west of 

 Carrizo Springs, and ten miles north of that point, on the ranch of Mr. 

 Vivian, produces a stream of excellent water four inches in diameter 

 from a well one hundred and seventy-five feet deep. This stratum of 

 sandstone ought to be reached at Laredo at a depth of from five hun 

 dred to six hundred feet. 



