Eocene Period, 56-33 million years BP. A fossil Knightia alta fish in a rectangular matrix. 318 grams, 17cm (6 3/4"). From the Pradi collection, Boston, USA; acquired during 1980s; from the Green River Formation, Wyoming, USA. Seasonally some 58 million years ago, in the Green river region of Wyoming, torrential rains would occur in the mountains; the rain would flow down the mountain sides and wide shallow lakes would form in the valleys below. When the dry season occurred, these lakes would dry up due to evaporation (similar to what happens in certain parts of Africa today"). Millions of fish would die in this short period of time and this climatic cycle happened over a 20-thousand-year period. Layer upon layer of mud was deposited over these years entombing all the fish; at a much later date volcanic activity uplifted this area to expose all those layers of now fossilised fish. [No Reserve]

Very fine condition.