" The total quantity of ore already extracted, chiefly from the three first mines, is not less than 925,000 tons: yet nothing but surface' or patch work' has yet been done ; all the mineral has been quarried from shallow openings in the sides of the iron hills ; no pumping machinery has yet been erected, and only recently have adits for drainage been begun. The surface-rock indicates in many points that but a portion of the most easily obtainable ore has been quarried ; and it is safe to estimate that several millions of tons are proven to exist in the three or four oldest mines, with every likelihood of vast quantities in the beds below water-level. In addition to this are hundreds of localities where iron is known to exist in-a belt of 30 miles in length; and at more than a dozen localities companies have been formed or mines commenced. Great skill is not necessary in working these ore quarries. The operation consists in blasting, from a ledge of ore, large masses, which are subsequently broken into fragments by other blasts, by the sledge, or sometimes, in the most refractory cases, by means of a fire of huge logs.
"At the Jackson mine, a hole 18 feet in depth and 2 inches in diameter, loaded with powder and exploded last March, brought down 4000 tons of ore. The holes are all bored with good steel drills, managed by two strikers and one turner. The fragments of ore are loaded into one-horse carts, hauled a few hundred feet to the railroad, thrown into six-ton four-wheel cars, and carried to the wharves at Marquette, where they are unloaded into pockets, or hoppers, or shutes, and thence into the vessels that transport them to the furnace on the lower lakes, or are transferred by wheelbarrow from the hoppers to the vessels or steamboats. The laborers at the mines receive S2 per day,
work ten hours, and pay $20 per month for their board. The average product of each laborer—including all, whose names are on the pay-roll,—miners, drivers, trackmen, repairers, &c.—is 2 to 21 tons of ore per day per man. In some cases an average of five tons per day per man has been taken out by a small gang. 91 cents per ton freight is paid on the railroad to Marquette, and the price of ore on the vessels is now $5 per ton." We might trace the Azoic belt around the great Appalachian basin, by continuing it from Michigan into Wisconsin, where the Lake Superior ores seem to exist in perhaps equal bulk ; but for all practical purposes in this connection it would be a useless expenditure of time and space. The data at command is limited; and the region about the Rocky Mountains, and the continuation of the gneiss, are more the subjects of speculation than scientific discovery.
There are, however, several important outcrops or anticlinals of the Azoic rocks within the area of the Palaeozoic, and which are even encircled by the coal formations of the West.
The Azoic rocks of Missouri, containing her immense deposits of iron and copper, belong to these isolated groups of gneissic and volcanic rocks, and do not belong to the Azoic belt surrounding the Palaeozoic rocks of the great basin which we traced from North Carolina or Georgia to Wisconsin, in following the metallic ranges of that forma tion.