Natural History - Amethyst Crystal Geode Section Group [20]

Comprising a cluster of large clear fluorite crystals with speckles of haematite; supplied in a labelled specimen tray. 48 grams, 48 mm



From Tri-State, U.S.A. Ex Mineral Imports, London, UK. Gregory, Bottley & Lloyd (Gregory's).

The rounded sandstone matrix with three Knightia alta specimens. 141 grams, 12.4 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.

Metalegoceras sundiacum with polished surfaces. 832 grams, 11 cm



From Maubisse Formation, Timor, Indonesia. From an old Oxfordshire, UK, fossil and mineral collection.