Green River Formation Has Given Us The Most Fish Fossils

Although there are many locations on planet Earth where fish fossils have been discovered, the Green River Formation is the only single location where most fish fossils have been found. This location was first discovered in the 1870s. Since then around 1 million fossilized fish have been found there. Along with a dozen fish species, many other fossils of birds, turtles, insects, salamanders, mammals, etc., have been found in the Green River Formation. Not just these, as many as 325 kinds of plant fossils have also been discovered at this old geologic formation.

A Little Information About Green River Formation

This is a rock formation that comprises of sedimentary rock layers. These layers were developed in a huge system of lakes. As per scientists, it is believed that Green River Formation was formed around 59 to 33 million years ago in the Eocene Epoch. Today, you can find Green River Formation covering parts of Utah, Colorado, and Wyoming.

Most of the fish fossils in Green River Formation are found in the Fossil Lake in south western Wyoming. Paleontologists split this area into two fossil zones. One zone was given the name ‘split fish layer’, which was full of fish and other fossils. The “split fish layer” zone has a depth of around 6 feet and its sediment is quite laminated. Fish fossils are mostly removed nearly whole from this zone. The other zone did not have as many fossils. It measured about 18 inches (called the “18 inch layer”) and by looking at the composition of the limestone, paleontologists believe this zone took shape in deep water further away from the shore. The 18 inch layer contains incredibly detailed fish, plants, and other fossils.

Fish Fossils Found In Green River Formation

Different types of fish have been found in the Green River Formation. But, there are two types of fish that are found in great numbers here, which are Diplomystus and Knightia. The first one, Diplomystus, was found by a renowned paleontologist Edward Drinker Cope in 1877. And Knightia was found by David Starr in 1907. Both these fish types were a genus of ray-finned fish. Ray-finned fish were those whose fins were supported by small bones. Modern day sardines, herrings, and alewives are distantly related to ray-finned fish. Knightia eocaena is one of the most discovered fossil fish in the fossil lake area.

At Buried Treasure Fossils, you can find many Green River Formation fossils. We offer a large selection of Knightia and other fish for sale. If interested, get in touch with us soon as fossil collectors are buying these fossils in huge numbers.