Florissant Fossil Beds National Monument - Fossils

The rich deposits discovered at Florissant Fossil Beds give us an unusually detailed look at life in an ancient North America. These impressions of prehistoric plants and animals are relatively young in geologic terms. The Florissant fossils hint at what life may have been like about 34 million years ago during the late Eocene Epoch; approximately 30 million years after the age of dinosaurs and at least 33 million years before humans appeared. Today most of Florissant"s fossils are exhibited and studied at various museums and universities. A small number are displayed in the park visitor center. Others, unfortunately, have been taken as private souvenirs over the years; what valuable information they might have provided cannot be known, for each fossil is an irreplaceable piece in the puzzle of the past. Fortunately millions of other fossils in yet undisturbed portions of the fossil beds are now protected by the park.

Impression and Compression Fossils of Plants and Permineralized Stumps of Redwood Trees

Fossils of an incredibly diverse mix of more than 140 species of trees and other plants have been discovered at Florissant. Most commonly fossil leaves are found, but fossil twigs, seeds, cones, flowers, and pollen grains also occur. Like the insects, plant fragments have usually been preserved as lifesize, color-enhanced impressions. A quite different type of plant fossil found at Florissant consists of massive petrified stumps of redwoods and other trees. They stand today where they were buried by volcanic mudflows millions of years ago. The stumps turned to stone as minerals seeped into the wood and gradually crystallized within woody tissue. The fossil record suggests that the ancient forest was not like any now in Colorado. In it grew many trees and shrubs whose closest living relatives are now found in widely scattered places such as the southeastern United States, Mexico and China.

Fossil Insects

Insects are rarely preserved as fossils because they are so fragile. But the volcanic ash mixture that fell on Lake Florissant was finer than talcum powder and ideal for the delicate job of preservaton. Thousands of insect fossils have been recovered from the fine-grained, fossil-bearing shales. An amazing number of insects species - up to 1500- have been identified. The insects are usually preserved as exquisitely detailed impressions in the shale, colored brown or black by a thin residue of organic matter - all that remains of the actually living thing. Some insects look perfect, others are crushed, and some are just parts: a delicate wing, a headless body. The fossils indicate that insects 34 million years ago were much like those today. However, many types that once lived at Lake Florissant no longer inhabit Colorado. Some like the tsetse fly, are gone from North America. Others are wholly extinct.