Rattler Gulch Limestone Cliffs ACEC

The Madison Limestone Formation across the road was deposited about 350 million years ago in a shallow sea and was uplifted about 65 million years ago during the Laramide Orogeny, when the Rocky Mountains were formed. During this uplift the cliffs were folded and faulted, adding to their geologic structure. Approximately 1635 feet of the Madison Formation are exposed here, and it is partly composed of the fossil remains of small marine animals. Erosional processes along the bedding planes reveal ancient sea floors. This outcropping is unique in its entire exposure, is given special emphasis and protection as an ACEC, and is used by universities and high schools for geologic study and investigations while also being available for public viewing and enjoyment.

Montana · United States