Wyoming Is Home to a 50-Million-Year-Old Forest

When people think of thick forests, towering trees, and lush rainforest understories, Wyoming isn’t the first state that comes to mind, thanks to its long (and somewhat agonizing) stretches of high desert isolation. But from the land that boasts not only the towering majesties of the Tetons, but the rugged canyonlands, stunning rock formations, and coursing rivers that crisscross the state, comes a completely different side of Wyoming's natural beauty — although perhaps a little more ancient than your typical bucket list stop.

If you live in or explore the Cowboy State for any length of time, you'll quickly discover that the state is rich with prehistoric sites, ranging from the subtle, yet remarkable, footprints at the Red Gulch Dinosaur Tracksite to the larger-than-life skeletons at UW's Geological Museum. In fact, many casual paleontologists and history buffs likely already know that Wyoming has an entire Dinosaur Trail to check out, packed with bones, fossils, and other fascinating prehistoric remnants. But modern-day fossil hunters in the Cowboy State aren't just limited to dinosaur bones when there's so much more hiding under the surface (literally).

In the stark terrain of southwestern Wyoming, a forest that predates human history by millions of years is preserved in stone. The Blue Forest near Fontenelle is not your average old-growth forest, though — it's ancient. Thought to be over 50 million years old, this now-desert landscape offers a rare peek into a time when Wyoming was a lush, subtropical paradise, home to towering trees that would eventually become some of the most beautiful and scientifically significant petrified wood in the world.

Eons ago, Wyoming’s landscape looked very different. The region was part of a larger, rainforest-like environment, and instead of the arid, rugged mountains of today, it was dotted with dense canopies and freshwater lakes. One of the largest of these was Lake Gosiute, a sprawling body of water that used to cover much of what is now southwestern Wyoming. Its shores were lined with the ancient ancestors of the modern pine conifers we know and love today, hardy sycamore, and unexpected species like magnolia and large sequoias.

This tropical environment — warm, humid, and rich with plant and animal life — was the perfect setting for the hardwood trees that later became the fossilized specimens now found in the Blue Forest. At times, intense flooding submerged the trees. At other points, volcanic eruptions blanketed the area with ash and buried the trees, preserving them in perfect detail. Over millions of years, these various geologic processes turned the ancient wood into stone. The result is a huge concentration of fossilized limbs and branches — one of the most extraordinary examples of prehistoric flora in the entire world.

What sets Wyoming's Blue Forest apart from other fossilized forests, like the portions of the Redwoods of California, is its color; specifically, the dazzling blue hue that "stains" many of the petrified limbs. The color is actually a unique fossilized crust that comes from blue chalcedony, a type of microcrystalline quartz that replaced the original wood during permineralization (the official term for the preservation process). Wyoming's perfect storm of volcanic ash and mineral-rich groundwater played a key role in this process, and the result is a collection of stunning petrified wood pieces that range in color from blues to purples, more reminiscent of geodes and gemstones than wood.

Because so many external processes have to happen in perfect harmony, petrified wood is actually relatively rare in most states. But unlike many other sites where petrified wood typically looks like what it is — solidified wood in natural shades of brown or red — the presence of blue chalcedony makes the Blue Forest incredibly special. Wyoming is one of only two known sites in the country where blue chalcedony can be found encapsulating fossilized wood in this way, drawing scientists, rockhounds, and curious visitors from all over.

A visit to the Blue Forest is a much different experience than ogling Yellowstone's petrified trees, which were buried in their full-grown prime by the hot, volcanic mudslides of the ancient Absarokas. It's also likely different from any other petrified forest you've heard of. You won't find any large stumps like those that were smothered in ash at Pompeii or smothered by the natural asphalt of the La Brea Tar Pits in California. Instead, all that remains are small, hand-held-sized remnants of a long-gone age, scattered about in Wyoming's harsh, unforgiving sagebrush and clay desert.

In fact, other than the petrified wood here, you won't find much else to indicate that this was once a literal rainforest. However, like so many other corners of Wyoming, the Greater Green River Basin is home to quite a few gorgeous "rock forests" instead.

Mushroom-like hoodoos, natural sculpture gardens, and epic red-colored formations galore dominate this slice of Cowboy Country. Beloved places like Chimney Rock, Steamboat Rock, and even the flat-topped Pilot Butte are all worth a visit, each hiding their own fair share of prehistoric secrets. History buffs will also love exploring the network of trails and the museum at the nearby Fossil Butte National Monument, which is open year-round and offers the added benefit of educational tours.

Every state and national forest in Wyoming has its own unique story to tell, but the one-of-a-kind, gem-like remnants found in the Blue Forest are a pretty cool opportunity for enthusiasts to bring a piece of Wyoming's prehistoric past home with them. And, at only an hour from Green River, Kemmerer, and Rock Springs, why not make a family day trip of it?

We think you'll love exploring the nature that exists here. And if you're in the mood for even more adventures nearby, be sure to check out our itinerary planner for additional recommendations!