A series where we take a #lookback at the stories and history of our community, brought to you by Mick Pryor, Financial Advisor with Edward Jones.

The Upper Wind River Valley is filled with history, some very recent involving humans and some very old, in fact, millions of years old perhaps before signs of life. Within the city limits of Dubois there are “red rocks” that you can touch in almost every direction. Even though these “red rocks” look similar, they are not.

The red beds east of Dubois certainly form impressive cliffs and a curvy road cluttered with bighorn sheep at times in recent years. These red beds form the Chugwater Formation, which includes red beds of Thermopolis and Dubois, Wyoming. Why the name Chugwater? Chugwater, Wyoming of course. The Chugwater Formation is a red sedimentary deposit containing sandstone, siltstone, and shale found throughout Montana, Wyoming, and Colorado.  Driving from “red rocks” about 10 miles east of Dubois to about 5 miles west of Dubois the Chugwater Formation is exposed on the south side of the highway. Oxidation of iron minerals in the rock or (natural rust), causes the red beds.

A large mass extinction event took place, creating the Permian Triassic boundary in the geologic record. This leads to the question of what was Fremont County like in the Triassic Period when these red beds formed. Imagine that today’s continents did not exist; instead, North America was near the center part of one large landmass called Pangea, which was oriented in a C shape north to south. A large ocean covered the other three-quarters of the planet. Pangea’s climate experienced temperature extremes with hot summers, cold winters, and very dry regions away from the shores. Monsoon-like seasonal climates occurred along the shorelines. In general, it was warmer than today. This is indicated because there is no evidence of ice caps on earth in the Triassic Period. There is evidence of everything from sand dunes to mud cracks to moist lush vegetation that later became coal. Ocean currents were likely simple considering there was one solid landmass oriented north to south. Amphibians and reptiles were around in warmer latitudes, like Fremont County. Some fossils recently found indicate marshy areas with ponds and lots of amphibians and reptile.

Next up for the Fremont County Museums

April 11, 7pm at the Pioneer Museum, “Lander in 1919”

Wyoming Community Bank Discovery Speakers Series

April 13, 2pm at the Riverton Museum, “Paint a Bird House”

Bailey Tire/Pit Stop Children’s Exploration Series

April 13, 10am at the Pioneer Museum, “Noble Hotel Walking Tour”

Wind River Visitors Council Adventure Trek Series

May 4, 1-3pm at the Pioneer Museum, “Historic Plant Day”

Bailey Tire/Pit Stop Children’s Exploration Series

The Dubois Museum, the Pioneer Museum in Lander and the Riverton Museum need your financial support. In the current economic environment the museums are more reliant than ever on donations from the private sector to continue to provide the quality programs, collections management, exhibits and services that have become their hallmark over the last four years. Please make your tax deductible contribution to be used specifically for the benefit of the museum of your choosing by sending a check to Fremont County Museums 450 N 2nd Rm 320 or taking it directly to the museum you choose to support.