Visitors who hike Isle Royale are often struck by its striated layout, its elongated forested-rock and lake patterns that parallel its backbone, the Greenstone Ridge. The island, it seems, must have been forcibly combed from northeast to southwest. The surface scene visible from the island's heights is the product of 10,000 years of natural sculpting, soil-building, and plant-pioneering and succession. Back then actually not long ago by nature's standardsthe island appeared beneath glacial ice, rising as the lake level dropped. The island developed soil and was colonized by plants and animals. Its many inland lakes first formed in basins gouged out by glaciers, and then began to shrink, as lakes and ponds inevitably do.

Beneath the ponds, the forests, and the light soil covering, however, is a story which must be told not in increments of centuries, but of millions and billions of years. The "ridge-and-trough" pattern of the rocks is the work of millions of years, pre-dating even the formation of Lake Superior and its islands. The story begins some 1.2 billion years ago with a great rift in the earth's crust which may have extended from here southward all the way to the Gulf of Mexico. As this series of cracks poured forth molten lava covering thousands of square kilometers, the land along the rift zone sank to form the Superior Basin, which has shaped all subsequent geological events in the region. The rock record of this cataclysmic happeningthe volcanics, sandstones, and conglomeratesforms Isle Royale's bedrock today.

Clues to the island's past abound. Smoothed, rounded, and even grooved rock belies the crushing power of the last major glaciation, know as the Wisconsinan. It ended here only a few thousand years ago. On the southwestern part of the island, where this glacier paused in its retreat, there are small linear hills made of its deposits.

The Stall Trail out toward Scoville Point passes three small pits in the rock. These form another clue, a clue to the Indians who mined copper on the island. The Indians came to the island only in mild seasons, taking what resources they could, then leaving before winter. The Indians mined here by about 2000 B.C., continuing for 1,000 years, and Isle Royale and Superior area copper made its way by trade as far as New York, Illinois, and Indiana. Indians were probably most active here from 800 to 1600. By the 1840s, the only Indian encampments white miners encountered were a maple sugaring camp on Sugar Mountain and a seasonal fishing camp on Grace Island.