The Green River Formation around Kemmerer, Wyoming produces the most beautiful fish fossils in the world: complete Knightia and Diplomystus on cream limestone, split out along the bedding planes. Several private quarries here run public digs where you split rock with a chisel and keep what you find, though the rarer material stays with the quarry. The federal land next door, Fossil Butte, is strictly look-only.
Fish, plants, insects · Eocene, ~52 mya
A commercial or managed site. You pay for access, and what you turn up is yours. Book ahead where the site asks for it.
Other places on the map within a couple of hours.
