Fossil Fish in Limestone Matrix

Genus: Knightia, Species: alta

Formation: Green River Formation, Thompson Quarry, Lincoln County, Wyoming

Age: Eocene Epoch, Cenozoic Period, 50 million years ago

Matrix Size: 10” by 8”, Fossil Fish length: 5”, Weight: 3 lbs

This Knightia alta fossil is larger than average. It is an extinct fresh-water ancestor of the modern herring. The fish has been sealed with a clear preservative but its color has not been enhanced. Note the small coprolite below the caudal (tail) fin. This piece is self-standing.

If you wish to see the fossil fish bearing layers of strata in their native environment, check out Fossil Butte National Monument, Wyoming. Or, if you want to go and dig your own fossil fish, check out Fossil Safari, Kemmerer, Wyoming. I dug fish at this quarry for 12 years, had great success and hope to go back there soon.