Natural History - Polished Fossil Orthoceras Column

Of irregular shapes with one polished face. 1.11 kg total, 9.2-10.7 cm



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

Comprising the negative impression of Knightia alta specimen on a rectangular matrix with enhanced details. 198 grams, 11.8 cm



From Wyoming (Green River Formation), USA. Acquired during 1980s. From the Pradi Collection, Boston, USA.

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.

Comprising six examples with this outer walls and the internal cavity filled with small lavender-coloured crystals. 338 grams total, 50-75 mm



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