The Bone Bed Unit. The bottommost bone-bearing layer/unit has also been the most prolific as far as quantity of dinosaur bones found. In the main quarry, over 2000 bones from more than 15 different species of Jurassic dinosaurs have been excavated, including Camarasaurus, Diplodocus, Apatosaurus, Camptosaurus, Allosaurus, Torvosaurus (the huge “T-Rex of the Jurassic”), Othneliosaurus, Dryosaurus and others yet to be identified.
Many Theropod teeth have been found in this layer, some with roots and others that had been shed or broken while the dinosaur was alive.
Ancient marsh area. This layer has been interpreted as a river system with a large marsh or very wet lowland environment that is immediately adjacent to the ancient river system channels and associated streams.
Periods of “calm” are made evident by the thickness and quantity of plant remains. Episodic dry, arid periods are noted by hardpans, mud cracks and evaporite deposits.
(left) Adult Camptosaurus skeleton.
Bone 'pile ups'. The bones in this lowermost zone are usually disarticulated, with bones from multiple species piled up against one another.
Recent excavations have indicated most bones were deposited by floods, with dinosaurs being caught up against or within existing depressions in the marshy environment or piled up in 'log jams' against large trees or tree limbs carried by the floods.
The Bone Bed Unit. The bottommost bone-bearing layer/unit has also been the most prolific as far as quantity of dinosaur bones found. In the main quarry, over 2000 bones from more than 15 different species of Jurassic dinosaurs have been excavated, including 
Ancient marsh area. This layer has been interpreted as a river system with a large marsh or very wet lowland environment that is immediately adjacent to the ancient river system channels and associated streams.
Bone 'pile ups'. The bones in this lowermost zone are usually disarticulated, with bones from multiple species piled up against one another.
