Editing Florissant Formation (section)

====Vertebrates====
The vertebrate fossils in the Florissant are predominantly small fragments of incomplete bones. There have been a few described species of vertebrates, mostly fish, but also birds and mammals.
The fish discovered at the site include [[bowfin]]s, [[Suckerfish (disambiguation)|suckers]], [[catfish]]es, and [[pirate perch]]es. Most of these were bottom dwellers, except the perches, and many were tolerant of poor water conditions. Most of the fish have been found in the same shale layers versus other shale layers. This could indicate that there were more tolerable times for fish populations over the history of the lake than other times.<ref name="book"/>

Three examples of birds have been found in the beds, including a [[cuckoo]]. Most of the skeleton was lost, but there were still enough diagnostic features to identify the bird. There are also examples of [[Coraciidae|roller]]s and [[shorebirds]]. Other birds were described in early literature from the 19th century, but the exact identification of these samples cannot be done due to lack of information.<ref name="book"/>

[[Mammal]]s are almost non-existent in the shales, with only one specimen of a small [[opossum]] being discovered so far.  In the lower mudstone units, there are samples of broken bones of a horse, a [[brontothere]], and an [[oreodont]]. The horse would have been small, about as large as a medium-sized dog, with three toes on each foot. All this information is based on a complete lower jaw. The largest mammal that has been discovered so far is a [[brontothere]], an elephant-sized animal with a pair of thick horns on the top of its head. All of this information is based on fragmented vertebrae and small pieces of tooth enamel. The oreodont, is an extinct family that resembles modern sheep and pigs. The only oreodont specimen is a jaw fragment.<ref name="book"/> Other mammals have been described in the formation based on teeth specimens. In all, around a dozen mammalian taxa have been discovered and described in the Florissant.<ref>Worley-Georg, M., & Eberle, J. J. (2006). Additions to the chadronian mammalian fauna, florissant formation, florissant fossil beds national monument, colorado. Journal of Vertebrate Paleontology, 26(3), 685-696</ref>

Surprisingly, no [[reptile]]s or [[amphibian]]s have been recorded from Florissant, where they would have been expected. No explanation for the lack has been proposed, given the nearly 40,000 specimens from this location held by museums. The toxicity of the water due to volcanic activity could be to blame, but there are documented cases of aquatic animals in the lake.<ref name="book"/>