Between 1 to 1 1/2 million years ago, sediments of slate and cherty iron carbonates were laid down on top of the granite and greenstone bedrock covering this area. Molten lava flowed over the land, seeping into great cracks on the surface and creating dikes. The land was then submerged under a great glacial sea, and more layers of sandstone and conglomerate rock were deposited on top. A catastrophe tilted this geologic layer cake, standing the rock layers almost on end at a 65 degree angle to the northwest. At this steep pitch, the layers slipped apart, and rain water seeped between the cracks. Over eons, the layers of iron carbonate rock oxidized, creating a band of low phosphorus hematite, a highly prized form of iron ore used in making steel. Above the footwall, the geologic intersection of a dike and the southern most edge of the iron formation, the greatest concentration of iron ore was found. This underground wealth, created eons ago, spurred the development of the Penokee Iron Range.