It’s one thing to read about something, but something else to actually do it, to be a participant versus just a spectator. In the case of the middle Miocene, we can read about it in lots of dry scientific dissertations, or we can visit it in our minds via a book like Opalescence.

But there is more that we can do. We can actually partake in the middle Miocene by visiting real places today that preserve remnants of that long bygone age*. The following are just such places.

The Mascall Formation

The Mascall Formation was laid down during the Mid-Miocene. It is located in the John Day Fossil Beds of Oregon. There you can actually hike the Mascall Overlook Trail and see the land where fossils from the epoch are revealed.

Although dramatic fluctuations in the global climate and regional volcanic activity continued, there were enough phases of moderate climate with ample rainfall and fertile soil to allow the growth of lush grasses and mixed hardwood forests. This savanna-like landscape was characterized by broad, level floodplains with scattered lakes. The new grass and forest environment allowed new types of fleet animals to emerge. These swift, long-legged, hoofed animals resembled their modern relatives: horses, camels, and peccaries. The Mascall environment also attracted newcomers: true cats crossed over from Asia, along with early elephant-like animals called gomphotheres. Other entire groups of animals, such as oreodonts, did not fare well in these new ecosystems, and their lineages went extinct.

Check out the hiking trails here (see Mascall Formation Overlook).

Ginkgo Petrified Forest

One of the largest petrified forests on the planet sits in the center of Washington State. The ancient trees were mineralized into rock during the great lava flows that swept the inland Northwest. In addition to petrified ginkgos (one of the oldest tree species in the world), the “rock forest” includes mineralized Douglas fir, spruce, walnut, and elm.

Here is trail info.

The Barstow Formation

The Barstow Formation is the source for the name “Barstovian”, the North American Land Mammal Age that is the focal point for Opalescence. Just north of the Mojave’s city of Barstow, there is a campground (Owl Canyon) and some lovely hiking trails. Probably the best known of the places to see is Rainbow Basin. Make sure to bring plenty of water.

Rainbow Basin has a diverse landscape of hills, canyons and washes. Multicolored rock walls and mesas are accented by changing light conditions, making for many photographic opportunities. The washes are good hiking trails for experiencing the area’s natural beauty.

Want to do more and perhaps bring back a souvenir or two? Try,

Sharktooth Hill

Managed by the Ernst Quarries, Sharktooth Hill is a great place to bring the family for some actual fossil digging, with a high chance of finding a, or many, nice specimens. By far the most common fossils you’ll find are Shark’s Teeth from the middle Miocene, especially those of the Mako. It’s not uncommon, though, to find big “Meg” teeth, big as your hand, from the largest shark to ever roam the earth’s seas, Carcharocles megalodon. You can make a reservation with the Buena Vista Museum of Natural History.

Virgin Valley

Opalescence was titled with the opals of Nevada’s Virgin Valley in mind.

Some 16 million years ago the Virgin Valley was formed during a series of rhyolite volcanic flows, resulting in a large basin enclosed by low hills. This basin contained a succession of lakes and forests of spruce, hemlock, birch, chestnut and even sequoia which were periodically buried by volcanic ash hundreds of feet thick. A large lake formed within the basin which deposited large amounts of diatomite, a biogenic form of silica. Seepage of super-heated water percolated through the ash layers, carrying silica to the long-buried trees.

This resulted in the slow creation over time of world famous opals.

Now, you can dig your own middle Miocene formed opals. There are several outfits that, for a fee, will allow visitors to buy a section of till or dig in the hill side for the gems.

*Something to be aware of: there is a real and valid debate about the ethics of digging fossils and other precious artifacts for private and/or for-profit (selling them) use. It removes them from study, display and protection by those who know how to do that, and their removal by unskilled means can destroy them, and others around them. However, my interpretation of the debate is that the main objection centers on the removal of larger pieces, and unique pieces (of any size), which should rightfully be in museums rather than gathering dust on someone’s shelf, not the small and very abundant type of fossils to be found at places like Shark Tooth Hill.

As always, should you decide to partake in any of these adventures, please, please remember to be respectful, stay on the trails, and as far as possible Leave No Trace.


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