MARRIAGE BETWEEN FOSSIL-LAGERSTÄTTEN AND ENVIRONMENT: INTERPRETING FOSSIL BUTTE NATIONAL MONUMENT TO INQUISITIVE VISITORS

The first thing that visitors usually see at Fossil Butte National Monument (FOBU) is a scenery of grass and sage, patches of conifers, and cedar groves nestled in the hillside crevices. This scene is vastly different from FOBU’s original depositional environment fifty-two million years ago. At that time, FOBU was covered by a large and shallow, sub-tropical lake, called Fossil Lake, which was part of the Green River Formation during the Eocene. Fossil Lake is a superb example of a Fossil-Lagerstätten as over a million specimens have been found here and the surrounding private and state quarries, ranging from common fish, like Knightia eocena, to rare, terrestrial animals like the early horse Protorohippus venticolus. What’s more, Fossil Lake preserves soft body parts that would otherwise be destroyed during fossilization, such as feathers, scale impressions, and cartilage bone. In return, these fossils tell us FOBU’s original depositional environment such as its freshwater lake and its warm and wet climate. When interpreting to visitors why FOBU is special, I always focus on this dual aspect between Fossil-Lagerstätten and environment. These two concepts are the big takeaway at FOBU and it’s important visitors understand this by the end of their visit. Not only does FOBU have an extraordinarily amount of fossils preserved in one locality, but these fossils tell us how warm and wet the locality was during the Eocene. FOBU gives us an ecological snapshot of a time far more warm and wet than its current situation.

These concepts can easily be understood at the research quarry and the fossil preparation lab. Visitors can watch well preserved fish excavated and prepared while they are taught important paleontology concepts such as why we collect them and how we uncover them. I also focus on the preservation of FOBU and why these organisms are important in determining ancient ecosystems. The visitor center also superbly displays the lush ecosystem of Fossil Lake such as its Fish and Plant Walls, its centerpiece display of the crocodilian Borealosuchus wilsoni, and its terrain models with life-like reproduction of organisms. These displays are fantastic for tours and help inquisitive visitors understand what life was like at Fossil Lake fifty-two million years ago.