When European explorers ﬁrst ventured into the upper reaches of the American Midwest, they dismissed the area as a barren, worthless wilderness. Then in 1844, William Austin Burt, a land surveyor, noticed a strange movement of the needle of his compass near what is now Negaunee, Michigan. A Native American led Burt to the site of a large deposit of iron ore, and so the mineral was “discovered.” For centuries, Natives had been using the iron ore for pigment and hammering it into beads, buttons, and chisels. In 1849, the ﬁrst blast furnace was put into operation, and large-scale mining began in the region. It continues to this day, even though the reserves of high-grade hematite iron are now exhausted and, instead, lower-grade taconite deposits are being worked. Iron ore was found in large deposits throughout the Lake Superior area—not only in the Upper Peninsula of Michigan but also northern Minnesota and northern Wisconsin. The region came to be known as the Iron Range, and over the past 150 years it has produced more than one billion tons of iron ore. The iron deposits were laid down in the Precambrian era, when the entire region was covered by a shallow sea and great masses of iron in the water accumulated over troughs ﬁlled with sediments of sand. When the waters eventually receded, vast thicknesses of iron and sand deposits were left in the ground.