There are no dinosaur bones here, they died out 5 million years earlier, but there are the most complete and well preserved fossils of many plants and animals, like crocodiles, fish, snakes and a bat. They died and sank to the bottom of the lake and were entombed in limestone. Follow the link http://www.nps.gov/fobu/photosmultimedia/index.htm to see how good the fossils look.
After the warm visitor centre, the walk up to the old fossil quarry was pretty chilly and the hut used by the old fossil hunters didn't look very comfortable. I don't want to be a fossil hunter if I have to live in this.
Much of southern Wyoming is bleak cold and barren, but atop one bleak cold hill is one of the world's richest fossil deposits at Fossil Butte (pronounced "beaut" if you don't mind!).