The sign contains a bulldozer to illustrate the power of glaciers to move large boulders.

The twenty-ton granite boulder near this trail arrived by glacier. Millions of years ago, great ice sheets descended from the Arctic across much of North America, shoving rocks and boulders far from their points of origin. As the glaciers advanced and retreated, they formed the landscape you see today.

Rocks scooped and dropped by the bulldozing action of glaciers are referred erratics.