The place:
The Morrison Formation is a 1.5 million square kilometre fossil deposit in western United States of America. It spreads from New Mexico in the south to Canada in the north and from Idaho in the west across to Nebraska in the east and is widely regarded as one of the best fossil beds in the world.

The finds:
These include 4 species of Diplodocus, two partial skeletons of Brachiosaurus, skeletons of adult and juvenile Stegosaurus, more than 60 part and complete skeletons of Allosaurus and a skull and associated skeleton of Ornitholestes. Numerous fossils of crocodiles, lizards, mammals and fish have also been discovered.

The environment:
In the Late Jurassic period the Morrison beds were laid down in a swampy lowland with meandering rivers. The rivers deposited silt and mud over the wide flood plains at high water burying the bodies of animals. Sediments were also deposited in occasional lakes. The formation includes shales, siltstones, limestones and sandstones.

The people:
The Morrison Formation took its name from the town of Morrison in Colorado where the first fossils were discovered in 1877 by Arthur Lakes. The same year the deposit became the focus for two rival palaeontologists called Othniel Marsh and Edward Cope. These were the first of many to study the Morrison Formation.