Claws on each finger of its wings indicate it was probably an agile climber and crawled along and under tree branches searching for insects. The limestone matrix is so fine grained that fossils include rare soft parts of complete insects and fallen leaves in spectacular detail.
Eocene epoch green river formation deposits are found in colorado wyoming and utah generally along the present day green river.
Green river insect fossils. Usnm pal 561330 fossil insect cenozoic era paleogene system eocene series green river formation. These photos from the national park service fossil butte national monument are examples of some of the many types of fossil insects preserved in the green river. As an important lagerstatte the green river formation sediments represent a continuous record of deposition that spans a 5 million year period from 53 5 to 48 5 mya.
View more green river animal fossils. The smithsonian is pleased to house 35 000 fossiliferous rocks collected within the green river formation in the states of colorado and utah. The fine grained rocks enabled the preservation of tiny details.
Specifically he donated at least 150 000 individual specimens from 18 green river localities or 5 500 to 8 200 individual shale samples trimmed and ready for accession per field season during his active collecting years. From 2004 to 2011 david kohls of battlement mesa co single handedly amassed thousands of fossil insects for the ucm. Green river fossil bat.
Fish fossils of diplomystus and knightia are found in fossil lake but not in lake gosiute. More than twenty two orders of insects are represented in the green river collection at the smithsonian institution in washington d c alone. The age of the green river formation is within the eocene period and these fossils specifically date.
National park service fossil butte national monument photograph. The fine grained limestones oil shales and marls of the green river formation are excellent rock types for preserving tiny creatures such as insects. This 5 5 inch long bat is the most primitive bat known.