Fossil Butte National Monument

Fossil Butte National Monument is located just 15 miles west of where our RV is parked in Kemmerer, Wyoming. It centers on an extraordinary assemblage of Eocene Epoch (56 to 34 million years ago) animal and plant fossils associated with Fossil Lake, an ancient shallow lake that was part of a group of three great lakes covering parts of Wyoming, Utah, and Colorado. The Monument preserves a wide variety of flora and fauna, including fish, alligators, bats, turtles, dog-sized horses, insects, and many other species of plants and animals which suggest the region was a low, subtropical, freshwater basin when the sediments accumulated over about a 2 million-year period.

Due to a very large amount of dissolved calcium carbonate in the waters feeding ancient Fossil Lake, and its shallow character, the water would evaporate quickly and float continuous deposits of calcium carbonate to the lakebed.  This formed a deep, mucky bottom which, when plant or animal life died and fell to the floor of the lake, would immediately cover it and prevent it from decomposing.  These layers of calcium carbonate (which eventually became limestone with pressure over the millenia) formed very thin, distinct layers, and each layer preserves the plants and animals that fell in it during the period it deposited.  The result is a spectacular, 18-inch thick geologic layer composed of many levels of fossils that have been nearly perfectly preserved - to the point that skin, feathers, scales and other features are easy to identify once the softer rock has been chiseled or brushed away.

The Visitor Center at Fossil Butte National Monument has an extensive collection of fossils, and is well-curated to explain how the fossils were formed, what plants and animals have been found, how the fossils were discovered, and how they are preserved.

We were fortunate with our weather because it was cooler than it has been recently.  While thunderstorms rolled in this afternoon, the morning was glorious.  The Monument sign was a work of art in itself, so Kathy posed with it and old Fossil Butte itself in the background:

Fossil Butte is aptly named, because the geologic layer in which the best fossils are found is at an elevation perhaps 500 feet higher than the valley floor; so quarries and fossil digs tend to be in the sides of cliffs or mountains, including the butte itself.

As we drove into the Visitor Center, Kathy spotted a herd of pronghorn deer grazing near the road.  

The park also boasts mule deer, white-tailed deer, elk, moose (yes, actually), black bear and mountain lions, not to mention beaver, badgers and raccoon.  We spotted moose, elk and deer scat on the trails as we hiked around; however, Kathy has a rule that David cannot post photos of poop, so you will just have to imagine those beautiful animal signs yourself.

We wanted to do the Fossil Lake hike, but first took the ranger's suggestion and drove to the far end of the monument, and then out a BLM road to a prominent ridge, and out the ridge to a lookout to get a view of the gorgeous landscape.  Here is Dusty doing his part to get us where we wanted to go:

At the top of the ridge, valleys opened up on all sides of us.  This view was west toward a beautiful pond --

-- and, beyond the pond, this lush green stream valley that just called to us, asking us to hike or drive down to explore its furthest reaches:

From the high point, we hiked on along ridge on the dirt road, and ultimately found a wooded area with perhaps a half dozen informal campsites.  This being BLM land and not National Park Service land, campers are permitted to hang out for up to 14 days enjoying this scenic beauty:

Walking back to the Jeep, we encountered a big round bush, thick with golden yellow flowers, and dozens of similarly colored butterflies in nectar-rapture:

We also found bushes and bushes of Saskatoon Berries, which you might remember we first encountered on our bike ride south of Slocan, British Columbia, and then picked buckets-worth after paddling Duck Lake near Creston, B.C.  However, due to the drier climate and higher elevation here, the berries weren't as soft and juicy as those we found in B.C., although they were very sweet.

We found another interesting plant on the same walk.  Here, Kathy admires the beautiful immature green cones of this pine, which occupied a lush sky island with other pine, spruce and aspen:

On our drive back down from the ridge, we stopped to admire the view to the southeast, with some of the fossil bluffs featuring prominently:

The view to the northwest was just as beautiful, but softened and rounded, with hints of volcanic activity:

Our next stop was to hike the Fossil Lake loop trail, and as we started, we saw that our destination would be one of the fossil bluffs we had just seen on our drive back down from the ridge:

This section of the monument has many spring-fed drainages which are frequented by moose, elk and deer.  Here you can see a stand of quaking aspen where the ground is wet enough:

Our trail eventually took us right through a aspen stand:

Once through the trees, our path rose until we could look back over them at the nearby hills:

At the top of our hike we reached an interesting, unannounced feature:  a fossil dig that has been enhaced with benches and an area for ranger to explain the process of finding and preserving the fossils. 

Two scientists have been digging in the Monument for nearly 20 years and have contributed much to the Monument's fund of fossils and information on display at the Visitor Center.

Walking back down the hill to a picnic area where we ate a quiet lunch looking out at the bluffs, the hills and the fields, watching a thunderstorm slowly blow toward us, we decided that this fossil stuff is way too exciting.  We've resolved to go fossil-hunting ourselves tomorrow.  We'll see what we dig up!