Natural History - Fossil Mosasaur 'Marine Dinosaur' Jaw on Composite Matrix

Comprising three rounded sandstone matrices, each with a Knightia alta specimen. 159 grams total, 75 mm each



From a Lincolnshire, UK, collection.

In southwest Wyoming (and parts of Colorado and Utah) in the Green River Formation are found some of the world's most outstanding specimens of fossil fish. The Green River system was composed of three lakes: Lake Ulinta, Lake Gosiute and Fossil Lake. These Eocene lakes lay in a series of intermountain basins formed by geological events that uplifted the Rocky Mountains during the early Tertiary time. The climate was much different from the desert-like climate of this area today. Both the fauna (crocodiles, alligators, boa constrictors and some subtropical fish families) and the flora (such as large palm trees) indicate a climate much like that found along the Gulf Coast today. Large amounts of ash found in the sediments indicate that volcanoes were particularly active at this time.

Polished to an oval cabochon and mounted to a pendant frame, collection number 219. 1.77 grams, 20 mm



Ex Miss Rawlinson in 1908. Acquired on the UK mineral and fossil market, since 1970. From the historic mineral collection of Richard Valentine Cain, London, UK, thence by descent. Accompanied by an original historic index file card.

A large section of Mosasaur prognathodon jaw with eight teeth, set in a composite matrix with applied plaster reinforcement. 2.32 kg, 48 cm



From a Cambridgeshire, UK, collection.

The Mosasaur is an extinct, large marine reptile dinosaur with a snake-like body, long snout and paddle-like limbs. found worldwide, they competed with other well-known sea predators of the Late Cretaceous, such as plesiosaurs and ichthyosaurs, for food, existing primarily on a diet of ammonoids, cuttlefish and fish.