Description
Mined from: Green River Formation, Wyoming, U.S.A.
Era: Eocene Epoch
Geological Age: Approximately 50–52 million years old
Description: Knightia eocaena is one of the most well-known fossil fish species from the Green River Formation, a series of ancient lake deposits spread across Wyoming, Utah, and Colorado. These small, schooling fish lived in large freshwater lakes during the Eocene, a time when the region had a warm, subtropical climate. Their fossils are preserved in fine-grained limestone, which captured exceptional detail—from delicate fin rays to individual vertebrae—making them a benchmark species for fossil collectors and paleontology education.
The Green River Formation represents a lacustrine (lake-based) sedimentary environment where periodic low-oxygen conditions at the lake bottom prevented scavengers and slowed decomposition. Fine carbonate mud settled over the fish remains, compressing them into thin, detailed impressions over millions of years. Knightia is often found in large numbers on single slabs, reflecting mass mortality events or natural schooling behavior, and is commonly associated with other species such as Diplomystus, which likely preyed on them.
Knightia fossils are often appreciated for their connection to ancient life cycles, preservation, and continuity through time. Many people are drawn to them as symbols of adaptation, flow, and resilience—representing life’s ability to persist and evolve through changing environments. Their clean, recognizable form also makes them a popular and accessible fossil for both new and experienced collectors.
Approximate Size of 1 piece: 50mm x 35mm x 5mm
Approximate Weight of 1 piece: 15g
Quantity: 1pc
We do our best to buy quality products- although not every rock is the same. If you choose to purchase the "staff pick option", we will select the best of the batch for you. Otherwise, it will be at random from the larger batch we have in stock.