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The following is intended only as a brief resume of the principal economic results obtained during the work of the field season of 1891, the details and general geology being left for the Annual Report. The first portion of the season was spent in a reconnoisance of Southwest Texas under instructions to examine the artesian water conditions, more especially south of the Southern Pacific Railway, between Corpus Christi and the Rio Grande. The remainder of the field season was employed in a detailed study of the Cretaceous deposits of Lampasas, Burnet and Williamson counties, with especial reference to their economic values.

The work assigned me in connection with the principal object, as already stated, was to study the Tertiary-Cretaceous section, eruptives, relations of the upper and lower Cretaceous rocks along the Balcones fault, the occurrence of oil, albertite, etc.

Beginning at Corpus Christi, detailed examinations were made along the Texas Mexican Railway to Laredo, thence along the International and Great Northern Railway to the Nueces river, and from this point up the Nueces and Leona rivers to Montell, Uvalde county. This was for the special study of artesian water conditions. After this the study of the Balcones fault and the upper-lower Cretaceous contact was taken up and continued from the mouth of Nueces canyon to Austin.

From Corpus Christi westward, along the Texas Mexican Railway, as far as eight miles west of Los Angeles, there are beds of clay, sandy clay, and sandstone, following one beneath the other in layers that incline very slightly downward toward the gulf coast. The western limit of the area occupied by these rock-beds bears southward from the point eight miles west of Los Angeles and northeastward from the same point. The limit of the area is shown on the face of the country in a decided landmark, consisting of bluffs and steep declivities facing toward the west. These clays, sandy clays and limestones will not bear water in quantities sufficient to be depended upon for artesian water purposes, although, in many places, they furnish good shallow wells. The white calcareous sandstone at the base of these deposits cannot contain any considerable quantities of water, because of its impervious character. From San Diego westward this sandstone may be penetrated, but it is uncertain whether water-bearing rocks can be found at reasonable depths beneath it, for to the west of this area a later deposit of gravel and sand occupies the surface of the country