This is one of the best areas of the state for rock and fossil hunting. Particularly abundant are Montana agates or moss agates—one of the state’s official gemstones. The best place to hunt these prized stones is along the banks and beds of the Yellowstone throughout this section as well as the tributaries that feed into the Yellowstone. To find these treasures, you have to know what to look for. It’s a good idea to visit a rock shop first and view an unpolished specimen. The rough-skinned translucent stones have been described as looking like a potato before being polished.
The best place to look for fossils in this area is at Makoshika State Park adjacent to Glendive. You must get a permit to collect any fossils in the park, and any rare or unusual finds should be reported.
Another excellent area for fossil hunting is the Strawberry Hills Recreation Area. This is part of the large Fort Union Formation predominant in the eastern part of Montana. Here the red “clinker” beds bear lots of surprises.
Near Colstrip look for abandoned “scoria” pits and mine tailings. These are very good places to search for fossils. Layers have been turned here that you would never get to otherwise. Be very careful when examining these areas as they are often populated by rattlesnakes. It is best to turn over stones with a rock hammer or heavily gloved hand as black widow spiders reside beneath. Avoid active mining areas, and check locally to avoid trespassing on private property.