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silver being only partially separated from the lead, and the latter, for want of a market, thrown aside as refuse, yields, as I am informed, a very handsome profit. The direction of this vein is nearly north and south.

The position of these two veins, as well as the character of the neighboring rocks, are shown in the accompanying Section No.---

About one mile north of Mr. Stephenson's mine, near the San Augustine Pass, several other veins are exposed at the surface. None of them, however, appear to have been much worked, although, from the character and thickness of the ore, they could no doubt be made highly profitable.

Silver is also found in connection with lead in Arkansas. It there, likewise, occurs in the vicinity of eruptive rocks.

Lead.-Besides the argentiferous galena above mentioned, lead has been found in several localities in Washington county, Arkansas. It there occurs mostly in the form of sulphuret. Specimens of this ore from that region were tested by myself, and found to yield near eighty per cent of lead. The same metal has been found in connection with the Mountain Limestone in the Cherokee Territory.

Iron, in the form of oxide, is very generally distributed throughout the rocks of this formation, and furnishes the principal portion of their coloring matter. This metal has been found in workable quantities in several portions of Western Arkansas and the adjacent Indian Territories.

Strata belonging to the Devonian and Upper Silurian Periods have not been encountered by myself in any portion of the region under consideration. Others, however, unequivocally Lower Silurian in their character, have been met with along the western base of the El Paso Mountains, a few miles north of Fort Bliss. These rocks are there found resting in immediate contact with eruptive rocks, and consist of upheaved and highly contorted strata of hard, compact, light gray and blue crystalline limestone. They are exposed only at intervals; in some places exhibit a thickness of about three hundred feet, and are traced in a northerly direction for the distance of ten or eleven miles. Near their junction with the igneous rocks they are highly metamorphosed, and exhibit no traces of organic remains, but at a little distance are crowded with well preserved fossils, among which I have succeeded in recognizing the following well known species: Orthis testudinaria, etc.

At several points along the western base of the Organ Mountains farther north, strata of the same lithological character were observed cropping out from beneath the fossiliferous beds of the Lower Carboniferous Group. No fossils, however, were detected in any of them.