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have no such evidence in the way of springs to prove their value, and no boring has been carried far enough to test the matter, although preparations are now under way to do so. No rocks of similar age have been observed in the Guadaloupes. We must therefore conclude that while the artesian conditions of the Central Basin are not unfavorable, the probabilities are against securing an adequate supply of water sufficiently free from mineral matter to be of use for general purposes (unless it be from the sandstones of the Guadaloupe Mountains, which would require sinking to impracticable depths in most places). All exceptions will be of purely local extent and will require much local topographic and geological work for their designation.

There still remains the area of the Staked Plains formation to be discussed, but our knowledge of its geology is too limited to permit anything but the most general statement. The upper portion of these plains is composed of strata of later Tertiary or possibly Quaternary age, underlaid by a conglomerate and sandstone of earlier date than the Trinity Sands, dipping southeast. It is this bed that furnishes the surface water of the Plains, and from it gush the headwaters that form the Colorado, Brazos, and Red rivers. The beds underlying this are probably Permian on the southern border, but newer formations may intervene towards the north. It is possible that this conglomerate bed may yield artesian water near the western border of the State, and I understand that one such well has been secured. It is my opinion, however, based on such knowledge as I can obtain, that the probabilities of artesian water on the Plains are rather unfavorable than otherwise.

It will require a considerable amount of work in western New Mexico to decide the matter finally.

The well at Pecos City most probably belongs to the series newer than that described under the Grand Prairie Region, and therefore gives us no clue to the area north of it.

The Trans-Pecos mountain district from the Guadaloupe Mountains to the Rio Grande consists of numerous mountain ranges and detached peaks which rise from comparatively level plains. These plains are composed of loose material which has been derived from the erosion of the mountains and sometimes has a thickness of over a thousand feet, as is proved by the wells along the Texas Pacific and Southern Pacific railways. The geologic formations of the mountains themselves consist of granites, sandstones, schists, and quartzites and Silurian, Carboniferous, and Cretaceous limestones. The whole area is faulted,