Natural History - Medium Sized Green Beryl Mineral Specimen Group [50]

Comprising two clusters of large yellowish-brown mica crystals on white quarts with three large translucent to white quartz crystals. 460 grams, 10.2 cm



Ex Gregory, Bottley & Lloyd (Gregory's).

Diplomystus sp. specimen on a rectangular matrix. 307 grams, 17 cm



From Wyoming (Green River Formation), USA. From an old Bristol, 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.

Clavilithes macrospira showing a good structure of the shell; supplied in a cardboard specimen tray. 263 grams, 13.5 cm



Collected between 1930 and 1960. From the collection of the palaeontologist R Gledhill.