Natural History - Black Obsidian 'Volcanic Glass' Specimen Group [100]

An irregular matrix with pyrite and arsenic. 205 grams, 85 mm



Ex Mineral Imports, London, UK. Gregory, Bottley & Lloyd (Gregory's).

From the lower jaw, displaying two teeth from Prognathodon sp.; repaired. 89 grams, 87 mm



From the phosphate mine region, Khouribga, Morocco, North Africa. Acquired 1950s-1960s. From an old Bristol, UK, palaeontological 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.

Two Green River fish specimens Diplomystus sp. in a matrix. 437 grams, 12.5 x 14.2 cm



From Wyoming (Green River Formation), USA. 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.