🦎 Amazing Fossil Monitor Lizard Found In Green River Formation This might be the most spectacular fossil to be found in what is now the Fossil Lake Safari quarry. It is an incredible Monitor Lizard that was unearthed about two decades ago. One of only three monitor lizards to ever be found in the Green River Formation it now resides in the Field Museum in Chicago. This 3 foot long specimen has such exceptional preservation you can even see preserved skin and its trachea. Check out FossilSafari.

⛏️🐟 Matt splitting open a slab containing a rare mass mortality layer of fossil fish from the Green River Formation. This particular layer, just a couple mm thick, is known at the quarry as the “mud layer” due to its distinct texture. Most ash layers in the formation are nearly barren of fossils—while the volcanic ash likely killed many fish by spiking the lake’s pH, the resulting acidic conditions often prevented proper fossilization. This layer, however, is an exception, preserving an abundan