(d.) The large bodies of silver-ore at Lake Valley, New Mexico; chambers in limestone, like c.

(e.) The Black Hawk group of gold mines, the Montezuma, Georgetown, and other silver mines in the granite belt of Colorado.

(f.) The great group of veins and chambers in the Bradshaw, Lincoln, Star, and Granite districts of Southern Utah, where we find a host of veins of different character in limestone or granite, with no trap to which the ores can be credited.

(g.) The Crismon Mammoth vein of Tintic.

(h.) The group of mines opened on the American Fork, on Big and Little Cottonwood, and in Parley’s Park, including the Silver Bell, the Emma, the Vallejo, the Prince of Wales, the Kessler, the Bonanza, the Climax, the Pinon, and the Ontario. (The latter, the greatest silver mine now known in the country, lies in quartzite, and the trap is near, but not in contact with the vein.)

(i.) In Nevada, the ore deposits of Pioche, Tempiute, Tybo, Eureka, White Pine, and Cherry Creek, on the east side of the State, with those of Austin, Belmont, and a series too great for enumeration in the central and western portions.

(j.) In California, the Bodie, Mariposa, Grass Valley, and other mines.[1]

(k.) In Idaho, those of the Poor Man in the Owyhee district, the principal veins of the Wood River region, the Ramshorn at Challis, the Custer and Charles Dickens, at Bonanza City, etc.

[Footnote 1:  See Redmond’s Report (California Geol.  Survey Mining Statistics, No 1), where seventy-seven mines are enumerated, of which three are said to be in “porphyritic schist,” all the others in granite, mica schist, clay, slate, etc.]

In nearly all these localities we may find evidence not only that the ore deposits have not been derived from the leaching of igneous rocks, but also that they have not come from those of any kind which form the walls of the veins.

The gold-bearing quartz veins of Deadwood are so closely associated with dikes of porphyry, that they may have been considered as illustrations of the potency of trap dikes in producing concentration of metals.  But we have conclusive evidence that the gold was there in Archaean times, while the igneous rocks are all of modern, probably of Tertiary, date.  This proof is furnished by the “Cement mines” of the Potsdam sandstone.  This is the beach of the Lower Silurian sea when it washed the shores of an Archaean island, now the Black Hills.  The waves that produced this beach beat against cliffs of granite and slate containing quartz veins carrying gold.  Fragments of this auriferous quartz, and the gold beaten out of them and concentrated by the waves, were in places buried in the sand beach in such quantity as to form deposits from which a large amount of gold is now being taken.  Without this demonstration of the origin and antiquity of the gold, it might very well have been supposed to be derived from the eruptive rock.