Lewis Overthrust

The Lewis Overthrust is a geological fault in Montana where older rocks have been pushed over younger rock formations across a vast distance. You can clearly see the different rock layers and recognize their different ages.

This geological structure formed millions of years ago when massive forces in the earth's crust pushed thick layers of ancient stone far eastward. The event left a clear mark in the landscape that helps geologists understand the earth's past.

The place draws geologists and students who come to observe the forces of Earth's history firsthand. The rock layers tell a story of massive movements in the earth's crust that remain visible today.

You reach the best viewpoints on foot via hiking trails that cross the region and show the rock edge directly. Visit on clear days when you can easily distinguish the different layers.

A fascinating detail is that very old stones lie directly on much younger layers, which normally does not happen. This reversal of the usual order makes the site especially valuable for scientists.