Natural History - Mixed Cut and Polished Agate Slice Collection [10]

Cleoniceras sp. displaying the distinctive pattern of the cross-section chambers, some iridescence to outer surfaces. 220 grams, 95 mm each



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

Comprising three rounded sandstone matrices, each with a Knightia alta specimen. 159 grams total, 75 mm each



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.

Displaying attractive banding, the colouring varying from light to dark purple. 232 grams total, 12-30 mm



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