Natural History - Fossil Ammonite Group in Matrix

The rectangular matrix containing four Knightia alta sp. fish. 955 grams, 24.2 cm



From the Green River Formation, Wyoming, USA. Ex 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: granite, collection number 536; two tiger's eye pebbles from North Transvaal, South Africa, collection number 203; selenite from Sahara Desert, Libya, collection number 349; amethyst from Brazil, collection number 360; arsenopyrite, collection number 471; stained calcite from Ghajn Tuffer, Malta, collection number 41; hematite, collection number 154; chryspoprase from North Transvaal, South Africa, collection number 195; sand crystals from Canterbury Sand Pit, Kent, collection number 173; pyrite from, collection number 343; topaz from Madagascar, collection number 294; and a large number of other mineral samples without collection numbers. 761 grams total, 14-66 mm



Acquired on the UK mineral and fossil market, since 1970. From the historic mineral collection of Richard Valentine Cain, London, UK, thence by descent.

Split to reveal the internal enhanced purple crystal cavity. 138 grams, 65 mm



From a Cambridgeshire, UK, collection.