Natural History - Grade A Cut and Polished Agate Slice Collection [3]

From Otodus obliquus Agassiz 1843 (mackerel shark). 174 grams, 77 mm



From the Ouled Abdoun Basin Formation (Phosphate beds), Oued Zem, Morocco, North Africa. From an old Oxfordshire fossil and mineral collection.

Comprising variously sized irregular chunks. 1.26 kg total, 21-40 mm



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

A negative impression of Diplomystus sp. specimen on a rectangular matrix. 441 grams, 15 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.