Green River, Wyoming
The Green River Formation from Wyoming is one of the most famous fossil strata in the world. Known for the thousands of fossil fish specimens collected there over the decades and for the well preserved and defined specimens of not only freshwater fish, but also insects, mammals, and plants. These specimens come from the Green River Formation exposures near Kemmerer, Wyoming and date to the Eocene Period (50-45 million years ago). The fish and other animals preserved in the layers all tell the story of the great Fossil Lake, that stretched from southern Wyoming, into Utah and Colorado 50 million years ago.