194 GEOLOGICAL SUEVEY OF THE TEERITOEIES. 



gneisses, -with some granites and occasionally cliloritic and talco-mica 

 schists, all more or less penetrated by quartz-veins. One of these veins, 

 near the summit, contains considerable quantities of translucent semi- 

 crystalline masses of hematite. These veins have been opened at various^ 

 places by prospectors ; but nothing of any value has yet been reported. 

 Several of these openings were examined ; but a few small scattered 

 crystals of pyrite were the only metallic indications seen. The so-called 

 " tin-mine " was not visited. Samples of its '' ore" appeared to be merely 

 massive hornblende, whose high specific gravity, due to the presence of 

 iron, probably originated the idea of its metallic character. A " graphite 

 mine," about twelve miles north of Ogden, near the Hot Springs, was ex- 

 amined, in company with its owners, and found to be a small opening in an 

 irregular quartz-vein which contains a few small tlakes of graphite, but 

 gives no indication of the presence of any valuable bodies of that min- 

 eral. On the whole, it appears probable that no valuable mines will be 

 found in the metamorphic rocks of this neighborhood. 



Immediately upon the metamorphics we find about 1,500 feet of heavy- 

 bedded quartzite, partly white, but mostly quite ferruginous. Its lowest 

 layers consist of a coarse conglomerate of large, red, gray, and white 

 quartz, and jasper i^ebbles. The upper portions are mostly finer grained, 

 with occasional streaks of very small pebbles. The lines of false bedding 

 are rather irregular, but mostly face the west or southwest, indicating 

 open sea in that direction at the time of their deposition. The only 

 fossils found in these beds are indistinct fucoidal markings, resembling 

 in general appearance the Arthropliycus Harlani of the Medina sand- 

 stone, but plainly not identical with it. From the character of the 

 overlying strata, I am inclined to refer this bed to the age of the Potsdam 

 sandstone. It forms the grand arch figured in the report for 1871. 

 Just to the south of this arch, the horizontal edges of its outcrop, in the 

 continuation of the axis of the arch, form a high clilf, over which the 

 waters of one of the small mountain-streams falls, first in a steep cas- 

 cade 52 feet, and then in one leap 263 — in all, 315 feet — to the bottom 

 of a narrow ravine. The tumbling rocks under the spray of the fall 

 were covered with numerous snails, {Helix, sp.) 



These quartzites are overlaid by something over 1,000 feet of gray 

 calcareous shales, without fossils so far as seen, and these by nearly 

 2,000 feet of comi^act blue and gray dolomitic limestone, partly oolitic in 

 structure, partly silicious and even cherty, partly filled with irregular 

 streaks and patches of ferruginous clay. In this immediate neighbor- 

 hood, this bed of limestone is exposed only where the strata have been 

 much disturbed, and it has consequently been mostly thoroughly shiv- 

 ered in every direction, though afterward recemented by the thin sheets 

 of calcite which fill all the crevices. Xo fossils were found in it here- 

 about, but a single specimen of Salysites catemdata, the characteristic 

 coral of the Niagara group, was obtained by the survey, in 1871, from 

 the upper part of what was supposed to be this bed, in Box-Elder 

 CaSon, some twenty-five miles north of Ogden. From the character 

 of the rock, however, I judge that at least the larger part of the 

 bed, together with the underlying calcareous shale, belongs to the 

 Quebec Group of the Lower Silurian age, which is so largely developed 

 along the Malade Valley farther north. It is not impossible that here, 

 as in the neighborhood of the Teton Mountains, nearly two hundred 

 miles farther north, the deposition of limestone might have been con- 

 tinuous from the Quebec epoch onward to the Niagara epoch or even 

 later. 



This limestone is followed by a second heavy bed of quartzite, mostly 



