Ancient Inland Seas

By Geology and Ecology of National Parks 2006 (approx.)

Three images of inland seas: one from 500 million years ago, one from 345 million years ago, and one from 170 million years ago. The inland sea covers the Black Hills region in every image.

Detailed Description

Three inland seas covered North America between 500 million years ago and today. Sedimentary rock formed beneath them The red box shows the location of the Black Hills region

Sources/Usage

Public Domain.

Images by Dr. Ron Blakey, Northern Arizona University, NPS: https://irma.nps.gov/DataStore/DownloadFile/426459