Natural History - Beryl Mineral Specimen Group [50]

Triangular tooth of Carcharocles megalodon displaying some good polished enamel and serrations to the edges. 66 grams, 76 mm



Property of the vendor's father, thence by descent. From the private collection of a New York, USA gentleman.

Comprising two cut and polished Aegasteroceras sagittarium ammonites showing good detailing. 261 grams total, 70-96 mm



From Conesby Quarry, Scunthorpe, UK. From a Lincolnshire, UK, collection.

Two negative impressions of Knightia alta specimens on a rectangular matrix. 312 grams, 13 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.