You are here

You Won't Find This On Your Hook....

Arvid Aase of Fossil Country Museum
Monday, July 20, 2009

National Parks aren't all about gorgeous landscapes, or American history. Sometimes they chronicle prehistoric history, such as the case withFossil Butte National Monument in southwestern Wyoming.

Here you'll find some of the world's best-preserved fossils in the flat-topped ridges of the region's cold sagebrush desert. Fossilized fish, insects, plants, reptiles, birds, and mammals are exceptional for their abundance, variety, and detail of preservation. The monument was established in 1972 to protect and preserve a portion of the Green River and Wasatch formations which contain a unique fossilized assemblage of organisms that once lived in or around Fossil Lake, an ancient lake of Eocene age. Many other clues to the environment of Fossil Lake and its environs are also preserved in the Wasatch and Green River formations.

The light-colored strata of the fossil-bearing Green River formation is exposed on the steep slopes of Fossil Butte, Cundick Ridge, Ruby Point, and elsewhere throughout Fossil Basin. The Wasatch formation underlies, overlies, and intermingles with the Green River formation, but, to the untrained eye, outcroppings of its colorful dull red, pink, lavender, purple, yellow, and gray strata appear to be scattered at random throughout the monument.

Although best-known for fossils, the monument also is home to approximately 300 elk in the winter. You can often see them from the visitor center.

As for the photo this week, it's a Knightia alta, approximately 12.5 cm long.

Several of the nearby public schools sections in Wyoming have the same stratum exposed and are leased for commercial fossil quarries. Back in the 1980s, the University of Utah's undergraduate course in evolution had a field trip to a quarry the first weekend: you could give each student a block of rock and a screwdriver or chisel, let them split off layers (or varves), and guaranty that they'd find at least 1 fish. That helped get their attention for the rest of the quarter. Grad students volunteered as van drivers: lots of distant relatives got fish fossils as inexpensive Christmas presents! One year we found a complete skate (ray), which became property of the state of Wyoming (as do all scientifically significant finds in the quarries).

There's also a huge coal strip mine a few miles south of FOBI.

Add comment


This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

National Parks Traveler's Essential Park Guide