Green Aventurine Crystal Tree on Amethyst

A rounded matrix with two Knightia alta fish with faint remains of another one. 62 grams, 91 mm



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.

Each specimen with multiple crystals and set in a foam insert within a labelled specimen box. 112 grams total, 21-23 mm



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

Mixed group including Perisphinctids indogermanus ammonite, Goniatite and Orthoceras. 584 grams total, 7.4-15.5 cm



From a collection acquired on the UK art market from various auction houses and collections mostly before 2000. From an important Cambridgeshire estate; thence by descent.