Daily Climate: The broad high prairie of eastern Wyoming and southern Montana was once the bottom of a shallow sea, a rich subtropical swampland for millions of years. Layers of plants began forming peat beds 60 million years ago, later to be buried and compressed into bituminous coal strata.
The Missouri River became the dominant stream as the Northern Rockies formed, with tributaries like the Yellowstone, Powder and Cheyenne rivers running north and east to meet it. Their erosion eventually left coal seams...