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the district and the determination of the probability of their existence in workable quantities, and finally the discovery of the existence of tin, which is in itself one of the most important of all.

TRANS-PECOS TEXAS.

Prof. W. H. Streeruwitz, having practically completed the topographic mapping of an important area, including the Quitman and Sierra Blanca mountains, parts of the Eagle, Diabolo, and Carrizo mountains, and the foot hills adjacent to them, was instructed to investigate its geology, with special reference to the valuable deposits of precious metals already determined as existing in it. He accordingly went to Fort Davis and got together his teams which had been at pasture, and after some trouble in securing assistants, finally started work with Mr. Ralph Wyschetzki as Assistant Topographer, and Mr. J. A. Taff as Assistant Geologist. Mr. Taff was given the study of the Cretaceous strata of the region, Prof. Streeruwitz working on the crystalline and older stratified rocks. The winter having been an unusually dry one, great difficulty was experienced in getting water at places convenient to the work without long hauling. The summer heat was also excessive, and lacked the invigorating breezes which are usual in that section. Taking it altogether, the work was done under very considerable disadvantage and even hardship, and it required the best of good nature and all the enthusiasm which the intensely interesting features of the geology of that region evokes to overcome them and succeed as fully as has been done.

The work that has been done includes the tracing and mapping of the various mineral veins of that district, specimens of all of which were taken and are now in the laboratory for analysis. Of the value of the district as a mining region there can be no doubt, and since excellent water occurs in the deeper workings and is found in the Quitman Valley, there is no longer any fear of a lack of this important item.

Besides this, the general geology of the region has been studied, and, as far as the limited time permitted, compared with similar adjacent areas; and while it is not possible to fully correlate the older rocks with those of other regions, much has been done towards the clear understanding of the structure and the stratigraphic relations of the various granites, porphyries, quartzites, marbles, etc. The fine porphyries and marbles have been collected for the purpose of showing their great beauty as building and ornamental stones.