This page has been proofread, but needs to be validated.
Chap. VI.
GEOLOGY OF UTAH TERRITORY.
281

The rocks in Utah Territory are mostly primitive—granite, brick-red jasper, syenite, hornblende, and porphyry, with various quartzes, of which the most curious is a white nodule surrounded by a crystalline layer of satin spar. The presence of obsidian, scoriæ, and lava—apparently a dark brown mud tinged with iron, and so vitrified by heat that it rings—evidences volcanic action. Many of the ridges are a carboniferous limestone threaded by calcareous spar, and in places rich with encrinites and fossil corallines; it rests upon or alternates with hard and compact grits and sandstone. The kanyons in the neighborhood of Great Salt Lake City supply boulders of serpentine, fine gray granite, coarse red ochrish pœcilated crystalline-white and metamorphic sandstones, a variety of conglomerates, especially granitic, with tufa in large masses, talcose and striated slates, some good for roofing, gypsum (plaster of Paris), pebbles of alabaster and various kinds of limestones, some dark and fetid, others oolitic, some compact and massive, black, blue, or ash-colored, seamed with small veins of white carbonate of lime, others light gray and friable, cased with tufa, or veneered with jade. The bottom-soil in most parts is fitted for the adobe, and the lower hills contain an abundance of fossilless chalky lime, which makes tolerable mortar: the best is that near Deep Creek, the worst is in the vicinity of Great Salt Lake City. Near Fort Hall, in the northeast corner of the basin, there is said to be a mountain of marble displaying every hue and texture: marble is also found in large crystalline nodules like arragonite.

Utah Territory will produce an ample supply of iron.[1] According to the Mormons, it resembles that of Missouri, and the gangue contains eighty per cent. of pure metal, which, to acquire the necessary toughness, must be alloyed with imported iron. Gold, according to Humboldt, is constant in meridional mountains, and we may expect to find it in a country abounding with crystalline rocks cut by dikes of black and gray basalt and porous trap, gneiss, micaceous schists, clayey and slaty shales, and other argillaceous formations. It is generally believed that gold exists upon the Wasach Mountains, within sight of Great Salt Lake City, and in 1861 a traveling party is reported to have found a fine digging in the north. Lumps of virgin silver are said to have been discovered upon the White Mountains, in the south of the Territory, and Judge Ralston, I am informed, has lately hit upon a mine near the western route. Copper, zinc, and lead have been brought from Little Salt Lake Valley and sixty miles east of the Vegas de Santa Clara. Coal, principally bituminous—like that nearer the Pacific—is found mostly in the softer limestones south of the city, in a country of various marls, indurated clays, and earthy sandstones. In 1855 a vein of five feet thick, in quality

  1. Magnetic iron ore is traced in the basaltic rock; cubes of bisulphuret of iron are found in the argillaceous schists, and cubic crystals of iron pyrites are seen in white ferruginous quartz.