| Oregon, in 1866, only produced, | $2,000,000 |
| Montana, with an area of 146,689 square miles, produced, in 1862, from her placers, | 300,000 |
| In 1863, | 8,000,000 |
It is impossible to give a correct estimate of the yield from Colorado for the year 1859, her first year, but the most liberal estimate would hardly place it above $800,000; the entire yield, including the quartz-mills, for nine years, from 1859 to 1868, as only $30,000,000. Of course there are several causes which it is not necessary to enumerate here, which operated fatally against any large yield from Colorado during these years.
The Black Hills proper has a superficial area of about 6,000 square miles. The bulk—we might almost say all—of the gold produced thus far from the Hills is from placer mines; the quartz interest has as yet hardly begun to be developed. By referring to the comparative figures, it will be seen that, considering her area, and the disadvantages which have surrounded her, the new El Dorado has done remarkably well this year, even if we confine her to the $2,000,000 which I have accounted for. She stands upon a very favorable footing with any of the auriferous districts during their early days. The quartz interest will give a large increase in the yield of bullion this year (1877), both in gold and silver and we may safely place the yield for 1877 at $7,000,000.
MINING UNDER LAKE SUPERIOR.
MINING UNDER LAKE SUPERIOR.
One of the most remarkable mines in America is the one known as Silver Islet in Lake Superior. It once was a small barren rock; its greatest width was seventy feet and its length eighty feet. It was only eight feet above the water, its position being about three-quarters of a mile from the main-land and exposed to a sweep of 200 miles of Lake Superior.
SILVET ISLET.
Operations were begun there on the first of September, 1870. On that date a party began the erection of cribs, and in thirty days there were put in place 460 feet of cribbing, thoroughly bolted together, filled with rock, and having an average depth of thirteen feet. Such an enormous extent of work was only accomplished by the force working unitedly, as one man, eighteen hours out of twenty-four. Inside of the crib-work a coffer-dam was constructed, enclosing seventy feet in length of the out-crop or back of the vein.