Natural History - Historic Kernite over Quartz Mineral Formation

The Knightia alta specimen on a sandstone matrix with remains of another fish. 1 kg, 17.5 x 14.5 cm



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.

The bright yellow crystals on white calcite matrices. 1.2 kg total, 12-60 mm



From Baja California, Mexico. Ex Mineral Imports, London, UK. Gregory, Bottley & Lloyd (Gregory's).

Complete Keichousaurus hui skeleton on a rectangular matrix. 2.4 kg, 31.2 cm



From Xingyi, Guizhou, China. Acquired 1950s-1960s. From an old Bristol, UK, palaeontological collection.

Keichousaurus was a late Triassic marine reptile, and a member of the Pleurosaur family, and went extinct 250 million years ago during the Triassic-Jurassic extinction event. They were specialised fish eaters, and were highly unusual amongst marine reptiles in that they gave birth to live young rather than laying eggs.