Читать книгу Boundary Waters Canoe Area: Western Region онлайн

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Inland seas covered what we now call the North Woods. Layers of sedimentary rocks were deposited at the bottom of that enormous sea. Called the Animikie Group, these rocks lie in a belt extending westward along the border lakes from Lake Superior to just south of Saganaga Lake, and then reappearing in the Mesabi Range south of the BWCAW. The Animikie rocks include the Pokegama quartzite, the Biwabik iron formation, and a sequence of shales and sandstones. Flint, too, is found in abundance in the vicinity of Gunflint Lake. Rich deposits of iron ore are scattered throughout northeastern Minnesota, upon which mining communities sprung up in the early 20th century. Iron ore became the economic basis for many communities in northeastern Minnesota and it is still one of the most important industries for the state of Minnesota. Iron ore is so concentrated in some places that it will cause a compass needle to be deflected from magnetic north. Magnetic Lake, in fact, received its name because of just such a phenomenon.