Natural History - Amethyst Crystal Geode Section Group [20]

Comprising a pair of cut outer layers with a polished face. 87 grams total, 13.5-15 cm



From an old Bristol, Uk, collection.

Comprising black euhedral crystals on a contrasting matrix. 148 grams, 70 mm



From Nenthead, Cumberland, UK. Collected in person from various parts of the world mainly between 1957-1966. From the private mineral collection of Stephen Atkinson, Harpenden, UK. Accompanied by a copy of a letter from the vendor giving details of him collecting these minerals throughout his life.

On a square sandstone matrix. 708 grams, 18 x 13.5 cm



Ex John Cummings, circa 2000. Property of an Essex gentleman.

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.