Menu Home About Us Payments Shipping Returns View Feedback Main DescriptionKNIGHTIA ALTA FISH FOSSIL IN A SHALE MATRIXFROM THE EOCENE EPOCH. 56 - 34 MILLION YEARS OLDFOUND IN THE GREEN RIVER FORMATION, KEMMERER, WYOMING, USAEACH PLATE APROX. 73 TO 86mm IN LENGTH Please be aware that size & shape vary between each plate.