Natural History - Mixed Mineral Specimen Collection [20]

Comprising: brown calcite from Chihuahua, Mexico; calcite from Tri-State, USA; grossular garnet from Chihuahua, Mexico; nailhead calcite from Tri-State, USA; pyrite; calcite. 568 grams total, 45-58 mm



From Chihuahua, Mexico; Peru, Brazil and Tri-State, U.S.A. Ex Mineral Imports, London, UK. Gregory, Bottley & Lloyd (Gregory's).

A Metacanthina barrandei trilobite showing shell structure, eyes and side antenna; on a matrix. 158 grams, 63 mm



From Hamar Laghdad Formation, Pragian, (Alnif), Morocco, North Africa. From an old Oxfordshire, UK, fossil and mineral collection.

Knightia alta specimen on a rectangular matrix. 397 grams, 13.3 cm



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.