Fossil Finding in Wyoming

So, the kids and I are on this road trip in the summer of 2020. We are basically quarantining ourselves in the camper; only popping into grocery stores (masked up!) and getting pay at the pump gas.

Mostly we’ve been staying in National Forests or BLM land. Boondocking as much as possible, like last night in the High Unita Mountains of northern Utah. This was one of my favorite campsites of the entire trip!

But, one thing that inspired our big trip along the continental divide this year was the PBS show Prehistoric Road Trip. We quite enjoyed the three part series and are visiting some of the out-of-the-way sites on the show. Digging our our fossils, then, became a big goal.

That is how we found ourselves at American Fossil Quarry near Kemmerer Wyoming. I did not book ahead, though it is possible on their website, but instead just showed up around noon on a random day of our trip. LOL. I lost track of the days of the week!

The folks at the quarry were super professional, all wearing masks, maintaining COVID measures like sanitizing, and keeping distances. We were shown the proper use of the tools, how to split the quarried stone, and had our own wire shelf on which to store our finds. I paid for two hours.

The geology around Kemmerer Wyoming features the Green River Formation. This shale was formed during the Eocene (56-33 mya) when the area was covered with three massive lakes – almost inland seas. This is after the dinos, folks, during a time when massive, odd creatures roamed North America. Watch the BBC’s Walking with the Beasts!

Anyway, those lakes had lots of fish, and we wanted to dig up their fossils. So, we chose a massive chunk of shale that had been removed from the quarry – the managers had areas sectioned off to organize which chunks were up for grabs. And then we proceeded to split it.

The technique was to rock-hammer tap around the center of a chunk until a crack forms and eventually splits the thing. Then, repeat with the remaining chunks until you’ve got fossils and pieces less than half inch thick. Split, split, split. The layers can be quite thin, so we may find fossils inside pieces in unexpected ways! The rock is very soft, almost chalky.

And we found lots of fish! The Knightia fish is the official fossil of Wyoming, and we found lots of them, or lots of PARTS of them. Finding a full fossil was exciting, and not too much of a rarity to make the whole thing worth while despite the wind and dust. We walked away with around 20 fossils to keep! Mostly small, and all Knightia but two which were Diplomystus – a slightly bigger fish with a distinct jaw.

At one point Zoe found a gorgeous Diplomystus in the center of a chunk we were hesitant to further split. But, it would be impossible to keep this 6 inch thick piece of rock, so an employee brought over a saw, and sliced into the stone an inch-ish, then helped Zoe tap it properly until it popped out of the main rock! So cool, and it allowed her to keep splitting and finding more fish layered in the stone.

Our two hours were nearly up as the sky quickly grew black and the wind picked up, so we used the provided barrow to wheel our finds over to the cutting area where an employee deftly squared off and separated our fossils.

We laid them out delicately on the lower bunk in the camper, and rolled up the dirt hill out of the quarry to beat the rain. It was a pretty steep access road, and I didn’t want to be stuck down there waiting for the road to dry. As it was, we spun tires a bit on the loose stuff.

I popped down to Kemmerer, then, and into Ace where they kindly let me just have their old boxes and packing material from the back room. It was perfect for packing the fossil slabs and storing them until we got home weeks later. Thank you small town Ace Hardware!

At home I treated them all with Vinac – a coating used to seal and solidify the stone with the fossil inside. It made what was a chalky, brittle, easily-broken matrix into a hard durable rock. Christmas gifts for everyone!

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