0.5 Detailed Fossil March Fly Insect Green River FM Uintah County UT Eocene Age
Location: Uintah County, Utah
Weight: 1.1 Ounces
Dimensions: 1.8 Inches Long, 1.6 Inches Wide, 0.4 Inches Thick (Plate)
Insect Dimensions: 0.5 Inches Long, 0.5 Inches Wide
The item pictured is the one you will receive.
50 million years old, Eocene age
March Fly Insect
Approximately 50 million years ago, a vast body of water known as Fossil Lake lay in what is now southwestern Wyoming. At its largest, the lake spanned nearly 930 square miles, though only about 500 square miles of its ancient sediments remain today. Within the central 230 square miles, remarkably fossil-rich layers reveal a record of life and environments that once flourished there — including shorelines, deltas, springs, and deep-lake deposits.
The lake’s unique chemistry slowed decay and discouraged scavengers, enabling the preservation of entire organisms in fine detail. Over time, thin, alternating layers of limestone accumulated on the lakebed, each representing quiet cycles of deposition. These finely laminated limestones hold the greatest concentration of fossil fish known anywhere in the world.
Discovered in the 1870s, the Fossil Lake deposits have yielded an astonishing diversity of life forms, capturing an entire freshwater ecosystem from the Paleogene Period. Fossils include fish, plants, insects, crustaceans, amphibians, turtles, alligators, birds, and early mammals—among them the oldest known pantolestid, a small otter-like creature.
The surrounding subtropical environment is equally well represented by fossils of early horses, snakes, lizards, bats, miacids (primitive carnivores), apatemyids (tree-dwelling insectivores), and over 325 varieties of leaves, seeds, and flowers. Together, these remains make Fossil Lake one of Earth’s most extraordinary natural archives—preserving a complete portrait of ancient life with exceptional clarity and balance.
