Dinosaurs of the Morrison Formation

By Charlie O’Brien

Are you interested in dinosaurs, and want to know more about the Bone Wars? This book is full of intriguing facts about the various dinosaurs fossilised in the Morrison Formation, and the two palaeontologists who spent years uncovering them - Edward Drinker Cope, and Othniel Charles Marsh. There is information about all the dinosaurs of the Morrison formation, such as the Alcovasaurus, Brontosaurus, Stegasaurus, and so many more amazing dinosaurs.

• Language: English
• Publisher: Charlie O’Brien
• Release date: Dec 14, 2021
• ISBN: 9798201920920

Book preview

THE MORRISON FORMATION

The Morrison Formation is a group of shallow marine, and alluvial sediments that, according to radiometric dating, ranges from approximately 156 million years old (at the base), to 146 million years old (at the top). It is late Oxfordian, Kimmeridgian, and early Tithionian stages of the Late Jurassic period. This sequence o sedimentary rock is the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone, and limestone in varying shades of light gray, greenish gray, and red. This formation had once been a semiarid environment, with wet and dry seasons.

The Morrison Basin where the dinosaurs lived stretches from New Mexico, all the way up to Alberta and Saskatchewan. It is centered in Wyoming, and  Colorado, but also has outcrops in Montana, North Dakota, Nebraska, Arizona, and Idaho. It was formed when the front range of the Rocky Mountains started pushing its way up West. The deposits from their east-facing drainage basins were moved along by streams and rivers, and ended up in swampy lowlands, floodplains, rivers, and lakes. The formation is close in age to the Solnhofen Limestone Formation in Germany, and also the Tendaguru Formation in Tanzania. It was named after Morrison, Colorado, where the first fossils were discovered by Arthur Lakes in 1877. This formation became the centre of the Bone Wars in 1877, which was a fossil-collecting rivalry between early palaeontologists (Othniel Charles Marsh, and Edward Drinker Cope).

The Morrison Formation held a large amount of gigantic Sauropods, including the Barosaurus, Brontosaurus, Camarasaurus, and the Diplodocus. There were thoropod predators in the area, like the Ceratosaurus, Stokesosaurus, and the Allosaurus. There were many other kinds of animals, like the frogs, salamanders, turtles, lizards, and pterosaur. Also, there were abundant vegetation, such as the fungi, mosses, tree ferns, and different types of trees.

Though many of the discovered fossils are fragmentary, they are good enough to help carve out an idea of what sort of flora and fauna resided in the Morrison Basin during the Kimmeridgian.

Garden Park, Colorado, was one of the three major sites excavated by palaeontologists Othniel Charles Marsh, an Edward Drinker Cope during the Bone Wars in 1877. Most of the specimens were too incomplete to classify (nomina dubia).  In 1992, a specimen of Stegosaurus stenops was discovered with its armour still in place, which finally confirmed that the species did, in fact actually have two rows of plates on its back.

The Dry Mesa Quarry, Colorado held a wide variety of fauna, as well as the most diverse set of dinosaurs from any other quarry in the Morrison Formation. The first dig was in 1972, by researchers of the Brigham Young University. The longest dinosaur known (Supersaurus),