The centre of the mining country is called the Superior country, or the northern peninsula of Michigan, but there is no reason to believe it is confined to this region. Coal and iron, the most valuable of all minerals are found in various places in the northwest. The principal and most valuable minerals found west of Mackinaw, are iron, copper, and lead. A general view of the mineral region may be found in Owen's Geological Survey of Iowa, Wisconsin, Minnesota, and Superior. Great beds of iron are found in ridges or cliffs, some of which rise up to an immense height. Some of these ore-beds of Lake Superior are fifteen feet in thickness, and one of them contains iron enough to supply the world for ages. Above them are immense forests, suitable for charcoal. The discovery of the iron mountains and mines of Lake Superior was made in 1846, but they were not fully developed until the year 1855, when the ship canal at Saut St. Mary was completed. The mines are from three to sixteen miles from Marquette, a thriving village of upward of one thousand inhabitants, overlooking the lake, about one hundred and forty miles above the Saut. The mine nearest the lake is about two and a half miles distant from Marquette, and bears the name of Eureka. The ore is said to be of surpassing richness, and yields an iron of the best quality, adapted to cutlery. The Jackson iron mountain, and the Cleveland iron mountain, are fourteen and sixteen miles distant. They send to Marquette an aggregate of one thousand tons per week. These mountains rise gradually to the height of six or seven hundred feet, and are a solid mass of iron ore, yielding from 50 to 60 per cent. of the best iron. The New England iron mountain is two and a half miles beyond the Cleveland mountain, and abounds with ore of equal richness. A mile or two further is the Burt mountain, and the same may be said of this, both as it regards quantity and quality, as of the others. A railroad has been constructed from Marquette to the iron regions, and immense quantities of ore and iron are transported over it daily. All the hills and mountains surrounding Lake Superior, abound in valuable minerals of which copper is the most abundant. It exists in every variety of form. According to the opinion of the lamented Houghton, this region contains the most extensive copper mines in the known world. The native copper boulder discovered by the traveler Henry in the bed of the Ontonagon river, and now in Washington, originally weighed thirty-eight hundred pounds. A copper mass of the same material, found near Copper Harbor, weighed twelve hundred pounds. At Copper Falls, there is a vein of solid ore which measures nine feet in depth, and seven and a half inches in thickness. At Eagle river a boulder was found weighing seventeen hundred pounds. The number of mining companies in operation on the American shore is upward of a hundred.