Visit the Monument's Research Quarry to see where some of the fossils came from/Patrick Cone

Many national parks preserve aspects of the past, and in the case of Fossil Butte National Monument, that past goes back 55 million years ago, a time when the landscape of western Wyoming was very different from the windswept plains dotted with sagebrush that we see today.

Wet and tropical was the predominant feature here during the Eocene, when odd-looking animals such as Coryphodon, a type of rhinoceros with no known relatives these days, bats, small cats known as Miacis, and a distant relative of today's coyotes, the Prototomus, roamed. But there also were fish, such as gar, herring, and even sunfish, ancient relatives of many of today's freshwater species. They swam in three lakes that no longer wet this landscape -- lakes named Gosiute, Uinta, and Fossil.  While those lakes are gone, the sediments they left behind have long since been compressed into stone, locking many of those species in place.

Bone hunters have been prospecting for these fossils since the mid-1800s, and while the bone wars here weren't as intense as those between Edward Drinker Cope and Othniel Marsh elsewhere in the Rocky Mountain region, they've generated a steady business for some.  Fortunately, enough of this vast, fossil-rich landscape remained available for Fossil Butte National Monument to be established on almost 8,200 acres back in 1972. 

Veer from your course up or down U.S. 89 for a short sidetrip down U.S. 30 to the monument and stroll into the visitor center and you'll be overcome by fossils of bats, turtles, fish, insects, and vegetation. You can even watch as paleontologists carefully wield drills and other tools to remove the substrate around fossils being prepared for display. Youngsters can use a rubbing table to create a fossil image they can take home as a momento of this unique landscape. (And don't forget your Passport to the Parks. The stamps here are some of the most interesting you'll come across in the National Park System; one stamp is the image of a Heliobatus radians, an ancient stingray. 

Then walk past a crocodile's 13-foot-long fossilized remains -- perched, seemingly, on its snout -- and into the exhibit hall that contains hundreds of fossils. Here are the amazing remains of turtles, fish, insects, and bats that are locked in rock. 

Don't leave the Visitor Center without your Passport stamp of an Heliobatus radians, an ancient stingray/NPS.

After exploring the fossil exhibit, and watching the 12-minute video that delves into the monument's background, head outside and onto the patio that wraps the center. You'll find a timeline running along the railing that notes the different periods of life that existed on the surrounding landscape tens of millions of years ago, as well as some of the life forms -- lemurs, elephants, various primates, deer, to name a few -- that were present during those times. Today plains and low hills extend in all directions, with taller mountain ranges off on the horizons. Two prominent formations -- the Green River Formation and Wasatch Formation -- are encased in this landscape, and within them are billions of fossils.

Once you've seen everything and asked all the questions on your mind, check to see if the monument's fossil quarry is open. At a small parking area a short distance from the visitor center you'll find a picnic area perfect for a quick meal. From there, a half-mile hike, mostly uphill, takes you to the quarry where you can see where some of the monument's fossils came from. During these programs, offered on Fridays and Saturdays during the summer months when the weather permits, rangers explain how fossils are pried from the sedimentary rock, and how researchers mark exactly where the fossils came out of the layer and how they were oriented.

As a bonus, you have sweeping views of the basin and range that once were underwater and teeming with life. From here you can see the Uinta Range in Utah and the Bear River Range in western Wyoming. And you can imagine how the low-slung hillsides in front of you cradled the prehistoric lakes. Harder yet will be trying to imagine forests of oaks, palms, willows and ferns that grew along the lakeshores, and the small horses that loped through them and the primates that climbed into the canopy. 

Watch the landscape carefully as you hike the trail up to the quarry, and back down, as these days pronghorn antelope, elk, coyotes, and skunks roam here.

Superintendent Nancy Skinner tells me just about 18,000 people a year make the short detour to Fossil Butte, usually from their trips south from Grand Teton and Yellowstone national parks, or north to those parks, 

"Most people find us along the way to Grand Teton or Yellowstone, or because they have an intense interest in science," she says. "This is like a biologist's dream come true."

If the fossil bug bites you, there are several other units of the National Park System well-worth your time. Dinosaur National Monument that straddles the Utah-Colorado border is not too terribly far south and showcases a hillside studded with the fossilized remains of some of the largest dinosaurs that walked the Earth. Down in Arizona you'll find Petrified Forest National Park with its colorful rock logs and fossils of animals that lived there about 225 million years ago.

Farther west of Fossil Butte, in Idaho, you have Hagerman Fossil Beds National Monument with its fossilized horses, mastodons, and saber-toothed cats. Go all the way to Oregon and you can visit John Day Fossil Beds National Monument with a variety of fossilized creatures, including ancient horses and false saber-toothed cats. To the east of Fossil Butte, in south-central Colorado, lies Florissant Fossil Beds National Monument, a haven for fossilized insects, flowers, and butterflies.

It'll take a while to hit all those locations, but if you're fascinated by the prehistoric past, you won't be disappointed.