Morrison formation

The Morrison Formation is one of the most famous and well understood formations because of the huge amount of fossils discovered there. Click on the critters below to find out more about them and their world!

This page is still a work in progress.


The lion of the Jurassic Morrison.
A rare predator every bit as fierce as T. rex
Forever famous as the dinosaur that’s “not Brontosaurus”
The cow of long-necked sauropods. Common and kind of boxy.
They might be the same animal, but more fossils are needed to be sure.
The first cousin of Ankylosaurus found in North America.
Ornitholestes: Bird robber, egg thief, or innocent bystander?


A small croc-ish thing that could run on its back legs in a pinch.
A croc-ish thing that might have a cousin in Europe.
A cat-sized not-a-croc that liked land more than water.

Other creatures

Frogs. The biggest is barely bigger than a quarter.
The first snake?
Morrison fish no bigger than a human hand.
The little guy, plus a few bones of a bigger one.
A very common turtle that could do turtley things, like tuck its head in its shell.