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Green River fossil plants

Nearly all of these 50-million-year old plant fossils, from the Green River Formation, belong to a group of flowering plants (angiosperms) called dicots.

Some of these plants may look familiar to varieties living today, but their leaf shape relates more so to the climate in which they grew rather than their evolutionary grouping.  

These and other fossils provide evidence that Utah, Wyoming, and Colorado were much warmer and wetter in the Eocene then today.

Green River fossil fish

Eocene rocks record Green River lake and shoreline sediments.

The Green River Formation preserves an entire fossil ecosystem in exquisite detail, and the fish are no exception.

Paleontologists have discovered numerous species from huge predatory fish to tiny herbivores. 

Many of these fish are extinct relatives of living groups, found throughout the world today in fresh and salty bodies of water.