Beach Bodies

The fossils of Frazier Basin. 

Living in Montana gives us easy access to beef, wild game, and freshwater fish. However, few people realize that millions of years ago, lobster and other marine life lived in the warm, shallow seas that covered most of Montana. “Bahama Montana” is a term coined by MSU geologist David Lageson. This was a time with a much lusher climate and where parts of Montana would have had some beachfront property on the edge of the vast inland sea.

Today, however, we live with the Bridger Mountains dominating our skyline and our lifestyle. An impressive option for enjoying the beauty of the Bridgers and having the potential of finding fossils is found by visiting Frazier Basin, a glacial cirque located just north of Sacagawea Peak.

The ridgeline surrounding Frazier Lake is intriguing. Layers of rock run vertically with sections that showcase waviness in the symmetrical lines. It’s an impressive display of how the horizontal sedimentary beds were pushed together, folded, and arched upward during the mountains’ formation. It’s an unusual order of rock layering.

Frazier Basin, Bridger Mountains, Geology

The oldest layer of rocks is now exposed at the top of the Bridger ridge. Within these rocks can be found fossilized stromatolites, one of the most ancient life forms. This blue-green algae dates back 3.5 billion years.

Below treeline, many other, “younger” fossils can be found by an observant hiker: horn coral, brain coral, brachiopods, bryozoans, and crinoids. Crinoids, or Lilies of the Sea, appear to be flowers, but were animals with tentacle-like appendages.

With so much history passing underfoot, remember to also look for the abundant wildlife. High on everyone’s list is the sure-footed mountain goat. Seeing the white furballs fearlessly traversing the impassable is mesmerizing. 

When planning your next hike, consider visiting Frazier Basin, where you can enjoy fewer people, impressive views, and a bit of Montana “beach walking.”

Patti Albrecht owns Earth’s Treasures in downtown Bozeman, where a vast array of fossils and other geologic gems can be found.