Knightia Alta Fossil Fish Mortality Slab with Calcified Gastropod, Green River Formation, USA

 This exceptional Knightia alta mortality slab originates from the renowned Eocene Green River Formation, a site celebrated for its exceptionally well-preserved freshwater fish fossils. Preserved in its original matrix, the specimen captures a moment on the ancient lakebed, offering a literal snapshot of life and death some 50 million years ago. The shoal of 5 partially intact Knightia show fine skeletal detail and subtle scale impressions visible, and the partial smaller fish remains and fragments provide additional context of a natural mortality assemblage. 
Adding to the ecological narrative, a sunning three-dimensional gastropod with a distinct white calcified tip is preserved in situ alongside the fish. The combination of fish and mollusk offers a rare glimpse into the Eocene lake ecosystem, illustrating both the inhabitants and the taphonomic processes of the time.

Specimen Details:

Dimensions: Overall matrix 215 mm × 130 mm × 13 mm. 
Each Knightia measures between approx. 70-100mm.
Gastropod: 3D specimen, 25 mm, with a distinctive white calcified tip

Age: Eocene (~50 million years ago)

Origin: Green River Formation, Wyoming, USA

Condition: Preserved in original matrix; excellent skeletal detail; visible scales and natural orientation

Please note: Every effort is made to photograph specimens in natural light for accurate representation. Slight variations in screen settings may affect color appearance.

Dimensions: Overall matrix: 215mm x 130mm x 13mm. Fish range from approximately 100mm to 70mm, Gastropod 25mm.