On the way across Oregon - a really big state - we stopped briefly at John Day Fossil Beds National Monument. A beautifully scenic place with the most diverse assortment of recent prehistoric mammals and plants on earth.
Stuff you've never even heard of - because they are discovering new species constantly. No dinosaurs here, just short faced bears, mastodonts, lava flows and volcanic tufts. When the volcanoes blew, they covered everything in ash that cemented and left amazingly detailed petrofied plant leaves, wood, even extinct avocados. John Day displays fossil nuts! If you can believe it.
Think the Tertiary version of the Burgess Shale. Extinct horses, rhinos, tortoises, elephants, cheetahs, and other wondrous critters we missed by just a few hundred thousand years. They don't have any evidence of alien trophy hunters bagging them all, but we know the truth.... ~~~~~~~~~~~