Natural History - Amethyst Crystal Geode Section

In a rounded sandstone matrix. 34.25 grams, 57 mm



From South West Wyoming (Green River Formation), USA. Collected between 1930 and 1960. From the collection of the palaeontologist R Gledhill.

Comprising three Knightia alta specimens, each on a rounded matrix. 177 grams total, 80-91 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.

Comprising four eggshell sections from Aepyornis. 49.2 grams total, 47-61 mm



From Madagascar. Acquired 1950s-1960s. From an old Bristol, UK, palaeontological collection.

The elephant bird was a gigantic, flightless bird, measuring nearly 10 feet in height, and lived on the island of Madagascar until it became extinct, possibly as late as the 17th century.