Mesa Gravels

Older – Niobrara
Pierre Shale

Mesa Gravels 2 Ma–10,000 years ago:
Many hilltops in the Park have chunks of reddish rock on top of them. These gravels
are the remains or evidence of glaciation. The rock layers here had already been uplifted and somewhat exposed when glaciers formed and moved across this area. The varied freezing and thawing cycles of these regional glaciers deposited significant debris on hilltops. These glacial deposits are named the Mesa Gravels.