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Knightia alta Mortality Plate | Green River Formation | Wyoming

Original price $399.00 - Original price $399.00
Original price
$399.00 - $399.00
Current price $399.00
Knightia alta unrestored specimens 100% Natural
Eocene (51.98 Million Years Ago)
Green River Formation, Wyoming, USA
From a newly discovered private quarry

Plate approx. size: 13.25" x 12"

Knightia approx. size: 4.25"-5"


Found in a newly discovered private quarry with beautiful reddish-gold toned iron mineral replacement of which this quarry is prized for.

We pride ourselves on delivering the highest quality specimens available. 


Due to the size of this specimen, it will be shipped in an internationally compliant wooden crate.

Please contact us for a specific shipping rate. You may opt in for in-store pickup to cut your shipping costs all together and pick up your specimen in person. You can pick up from our store location in Kemmerer, Wyoming, or we deliver to both the Denver Gem & Mineral show in the Fall and the Tucson Gem & Mineral show in the winter. For any questions, please don't hesitate to contact us directly.


Order Clupeiformes, Family Clupeidae
The Clupeidae family has an estimated 50 modern freshwater species. Clupeidae species can lay as many as 200,000 eggs at once, allowing species to multiply quickly. Modern species are also prone to mass die offs.
K. eocaena is:

  • The most common fish found from Fossil Lake.
  • The most commonly found articulated vertebrate fossil in the world.
  • The Wyoming state fossil.

Both K. eocaena and K. alta are frequently discovered in mass mortality plates, some containing up to 100 fish per square meter. This suggests that, like their modern relatives, the Knightia species were sensitive to environmental changes.
K. eocaena specimens of all sizes are found in mass mortality plates, indicating this species schooled as both a juvenile and adult. The average adult size of K. eocaena specimens is about 6 inches, though specimens as large as 10 inches have been found.