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also mentioned above in the Carrizo group south of the Texas & Pacific Railroad. In addition to these I may mention more remote granitic mountain groups and mountain ranges in Trans-Pecos Texas, which, although separated by very extensive flats, and then covered by several thousand feet of sand, clay, gravel—in short, detritus of any kind— leaving hardly any connection by lower granitic ranges covered up by later deposits.

The Wiley Mountains southeast of Van Horn are in fact only a portion of basaltic upheavals connecting the mountains west of Valentine with the Apache group through the Chispa range.

I had not the time to go beyond a hurried reconnoitering, which, however, proved that the limestone flanking the west slope, which on the north side extends towards Kent, on the Texas Pacific railroad, rests also here unconformably directly on the crystalline schists, which, however, in their upper portion are more decomposed than at other places observed changing into micaceous sandy shales.

A basin on the east side of these western flanking cliffs, where it is not covered by recent deposits, displays a granite bottom broken up and surrounded by intrusive, protrusive and extrusive basaltic eruptions, the granite as well as the basaltic rock showing many phases of contact metamorphism. The granite rises to the east of this peak, and by reason of not having been subject to equally strong destructive forces as the western part, shows plainly the action of the protrusive influence of the later volcanic eruptions by the bends and folds in the lower and the rents in the upper portions. Further east the granite slopes down and disappears again under many miles of the flat between the Wiley and the Apache mountains, which, as is usually the case, has obliterated all visible connection between the two mountain groups. The connecting traces between the newer eruptive material along the Rio Grande and the Apache group, we find in the Chispa range near Chispa Station on the Southern Pacific Railroad and in the Van Horn Mountains, where we also meet granite trachitic and crystalline schistose rocks.

ECONOMIC GEOLOGY.

As far as the ore-bearing character of the mountain ranges and groups, mentioned in this preliminary report, is concerned, I regard the Carrizo group south of the Texas Pacific Railroad an outspoken mineral district. The little prospecting which has been done in these mountains has brought very good results. Uncle Jake's diggings showed good silver bearing copper ore last summer, though the shaft was still say fifteen or twenty feet from the main lead, and the prospect near the railroad six miles west from Van Horn, sunk on an outcrop of iron (magnetic and hematite) two to three feet wide, carries some silver close to the surface, and Anglesite (sulphate of lead) crystals