The White River Badlands of South Dakota erode fast, and what comes out is one of the richest mammal fossil records on the continent: early horses, rhinos, oreodonts, and the false sabre-tooth Hoplophoneus. Fossils genuinely lie on the surface here. LOOK ONLY inside the park, and there is a public programme where you can report a find and have a palaeontologist come to it, which is a much better outcome than a pocket.
Oreodonts, nimravids, horses, rhinos · Eocene to Oligocene, ~34 mya
See it on the map
Other places on the map within a couple of hours.
