Yes! These are strange words, but fitting for a rock formation that contains such unusual fossil specimens. You can find the definitions of these words by reading this article on the Green river Formation here. You may also want to check it out just to see the amazing pictures of fossil lagerstatte, or exceptionally well-preserved fossils. These truly are exceptional!
The Green River Formation is known for its coals and oil shales, not just its fossils, but 50 million years ago, when the Rockies were young, it was deposited as muds and silts eroded down the sides of these newly minted mountains and deposited in intermountain basin lakes. It was warm and humid though, even in this environment, which allowed for copious amounts of vegetation to thrive as well as a very diverse portfolio of animals and insects.
