Marquette is the only point on Lake Superior where the iron ore deposits have been worked. There are deposits of iron in the mountains back of L'Anse, but this wonderful region leaves nothing more to be desired for the present. At a distance of eighteen miles from the lake, are to be found iron mountains named the Sharon, Burt, Lake Superior, Cleveland, Collins, and Barlow, while eight miles further back lie the Ely and St. Clair mountains. Three of these mountains are at present worked, the Sharon, the Cleveland, and the Lake Superior, and contain enough ore to supply the world for generations to come. The mountains farther back embrace tracts of hundreds of acres rising to a height of from four to six hundred feet, which, there is every reason to believe, from the explorations made, are solid iron ore. The extent of the contents of these mountains is perfectly fabulous, in fact, so enormous as almost to baffle computation. The ore, too is remarkably rich, yielding about seventy per cent. of pure metal. There are now in operation at Marquette three Iron Mining Companies, and two blast furnaces for making charcoal pig iron, the Pioneer and Meigs. The Pioneer has two stacks and a capacity of twenty tons of pig iron per day; the Meigs one stack, capable of turning out about eleven tons. The Northern Iron Company is building a large bituminous coal furnace at the mouth of the Chocolate River, three miles south of Marquette, which will be in operation early in the summer. Each of the mining companies, the Jackson, Cleveland and Lake Superior, have docks at the harbor for shipment, extending out into the spacious and beautiful bay which lies in front of Marquette to a sufficient length to enable vessels of the largest dimension to lie by their side and to be loaded directly from the cars, which are run over the vessels and dumped into chutes, which are made to empty directly into the holds. The process of loading is therefore very expeditious and easy. The amount of shipments of ore for 1859, from Marquette to the ports below, reaches 75,000 gross tons in round numbers, and the shipments of pig iron, 6,000 gross tons more. To this must be added the amount at Marquette when navigation closed, the amount at the mines ready to be brought down, and the amount used on the spot. This will give a total product of the iron mines of Michigan for the past year of between _ninety and one hundred thousand tons_. These mining companies simply mine and ship the ore and sell it. Their profit ranges between seventy-five cents and one dollar per ton. The quality of the iron of Lake Superior is conceded by all to be the best in the world, as the analysis of Prof. Johnson, which we reproduce, shows. The table shows the relative strength per square inch in pounds.