Park Archives: Florissant Fossil Beds National Monument

To leave a record of our experience is a very human desire. Early humans painted cave walls and etched in rock the events of their lives. In Colorado some of these historic stories in stone date back 4,000 years. But the picture-perfect wasp records events even 10,000 times older than that. Here, beneath pine covered hills and grassy meadows in south central Colorado, lies one of the world's richest fossil deposits. Remnants of an ancient world lie just below your boots.

Florissant Fossil Beds National Monument has yielded over 50,000 museum specimens from fossils of over 1,700 species—1,500 insects, 150 plants, and one of the world's only known fossil records of the tsetse fly, now found only in equatorial Africa. Here, no big bones stick out of the ground, but delicate fossil insect wings and finely veined leaves lurk beneath your feet, deep time's secrets locked in paper-thin shale. This world-class snapshot records Eocene Epoch life here 34 million years ago (mya).

WHAT WAS THE EOCENE? Keep in mind: here didn't look like here 34 mya, and what was here was vastly different. Redwood trees in Colorado, you ask? Similar redwoods now grow only in a thin belt on the California and Oregon coasts but exist here as fossil stumps, many still beneath the valley floor. No doubt the tsetse fly thrived because here was warm-temperate then, not today's cool-temperate highlands. In the Eocene Epoch—55 mya to 33.8 mya—warm-temperate forest reached the Arctic. And these fossil plant communities are much like today's plant communities in northeast Mexico, southern Texas, southern Appalachia, and eastern Asia. They represent the end of the Eocene, with global climate set to cool dramatically over millions of years. For planetary life this would be the biggest event since the extinction of dinosaurs 65 mya.

STRATIGRAPHY In 1669 the Danish geologist Nicholas Steno described how younger rock layers—strata—usually lie over older rock layers. Stratigraphy is the study of rock layers and layering and can show sequences of events like volcanoes or how lakes come and go over time. Shale formed from very fine volcanic ash and diatoms (microscopic algae) settling to a lake bottom, which cemented our wasp's great legacy.

A massive volcanic area—the Guffey Volcanic complex—existed 15 miles to the southwest 34 mya. The eruptions mixed ash, water, and possibly snow to create massive mudflows called lahars. They covered today's Florissant. The volcanic sediments broke down to soil, in which forests grew. Streams flowed in the forests. Mammals of the forest died near the streams, became buried in stream deposits, and were fossilized. The stream deposits were covered by more mudflows.

Powerful, destructive, and creative, lahars are mud flows from the slopes of volcanoes. They can move 150 mph down the slopes and carry car-sized boulders. A lahar from the Guffey volcano entombed ancient redwood trees in up to 15 feet of mud and volcanic debris. Eventually the parts of trees encased in mud would become petrified. A later Guffey lahar dammed a stream, creating Lake Florissant. In its bottom sediments many insect, leaf, and fish fossils began to form.

Fragile, paper-thin shale that formed on the bottom of Lake Florissant preserves delicate fossils. The shale formed from repeated microlayers of clay and volcanic ash—finer than talcum powder—overlain by films of the skeletons of dead diatoms. Sticky, surface mats of the dead algae trapped insects and leaves, then sank. The shale's delicate, fine-grained layers preserve tiny features in great detail. Many Florissant fossils look like realistic paintings or exquisite drawings.

EOCENE Eos=dawn + cene=new: The Eocene Epoch (55 mya-33.8 mya) is named for the dawn of small mammals. The climate was warm, sea level high, oceans warmer than now, and continents on the move. Glaciers began to form in Antarctica. In the late Eocene, global climate was set to cool significantly.

34 MYA a different world Florissant Fossil Beds may give clues about how an ecosystem responds to climate change. Soon after fossil beds formed here 34 mya, just as the Eocene gave way to the Oligocene Earth's climate cooled rapidly, by geologic measures. Where relatives of fossil plants and insects now live may show response to changing climate. We can compare this fossil site to others formed after climate cooled. So, even something "as old as a fossil" can be relevant and full of information today.

HOLOCENE Holos=entirely + cene=new: The Holocene Epoch is recent time, the last 10,000 years. An important thing these fossil beds can show us is how life adapted to the rapid climate change that took place soon after 34 mya. Compare: Eocene North and South America did not have a land bridge—today's Central America.

Humans are curious, exploring outer space, ocean depths, and even our own genes. Untold discoveries remain here at Florissant. Beneath this valley and rolling hills lies an ancient world, a 34-million-year-old ecosystem. Remarkably, scientists can describe the ecosystem in detail—despite such deep time—because so many of its working parts survive in stone. These fossils are not for burning for fuel. These fossils fuel our understanding and imagination. Their high biotic diversity tells of a warm-temperate past in a place that is now cool-temperate. They show organisms whose relatives still live here. They show others that no longer exist. Still others now exist only in other parts of the world. Tsetse flies fossilized here but don't live in North America. They live in equatorial Africa. Some secrets do remain: No fossils of reptiles or amphibians have been found here. Discovery goes on and on, with an active paleontology program.

THE BEECH FAMILY
Broadleaf plants, not conifers, were most diverse here 34 mya. A now-extinct member of the beech family, Fagopsis longifolia, was common. Its fossils have different plant organs attached, showing stages of the tree's reproductive cycle. This is very unusual and therefore significant. No fossils of its wood have been found with organs attached, so its wood is a mystery.

A VARIED ENVIRONMENT
Fossilized horsetails and cattails probably grew near ancient Lake Florissant or near streams. By contrast, fossil oak tree leaves show that hillsides may have been comparatively drier—as they are today.

Fir pollen suggests that cooler conifer forests may have existed on the upper slopes of the nearby volcano. The biologically diverse fossils show that the ancient environment was diverse.

ANOTHER CONTINENT
Like the tsetse fly, the golden rain tree no longer lives on the North American continent. It now lives only in eastern Asia—providing a clue to how plants dispersed in the past.

Today's park landscape features mountain meadows and rolling hills forested with ponderosa pine, spruce, fir, and aspen. These trees stand in stark contrast to petrified giant sequoia stumps from the ancient ecosystem these fossil beds preserve. And those petrified stumps stand in massive contrast to the delicate insect and leaf fossils.

It took 50 years of advocacy by many scientists and other people to get the fossil beds protected in 1969, in order to prevent irreplaceable loss. You can help protect this precious national heritage. Do not collect or damage the fossils, petrified wood, or other natural or historical features. And please report any violations you see to a park ranger.

Fossils from Florissant are in over 20 U.S. and U.K. museums and universities. Harvard University houses 8,000 fossil insects that paleontologist Samuel Scudder found in the late 1800s. T.D.A. Cockerell of the University of Colorado, Boulder, and Harry MacGinitie, of the University of California, Berkeley, later studied fossils here.

Park staff inventoried and photographed over 5,000 significant fossils at 17 museums to create a virtual museum and research database. To explore it go to www.nps.gov/flfo.

Fossils are best seen here in the visitor center, in the outdoor exhibit area behind the visitor center, or on the onemile Petrified Forest Loop. Get out on the park's 14 miles of trails (get a trail brochure at the visitor center). You may see an elk, black bear, coyote, badger, porcupine, tassel-eared Abert's squirrel, golden eagle, red-tailed hawk, or mountain lion. The altitude is 8,500 feet above sea level, so pace yourself, drink lots of water, and use sunscreen.

The wheelchair-accessible Ponderosa Loop starts behind the visitor center outdoor exhibit area. This half-mile walk goes through montane forest. On the one-mile Petrified Forest Loop you can see a fossil excavation site, the Big Stump (38 feet in circumference), and other massive stumps.

Schedules of ranger programs and hikes are posted in the visitor center, open daily except Thanksgiving, December 25, and January 1. Exhibits there show how fossils form. Find out more in books, videos, DVDs, and other items sold there. Also check on educational programs, field seminars, and the Junior Ranger program.

The 1878 Hornbek Homestead recalls pioneer life. Adeline Hornbek and her children farmed and ranched here. See their original cabin and root cellar and three historic buildings moved here from local ranches.

Services are available two miles north of the park in the town of Florissant: gasoline, restaurants, and convenience stores. Lodging is available in Woodland Park and Colorado Springs east of the park. Public and private campgrounds are nearby.

The contents of brochures, site bulletins and trading cards (denoted with a colored caption) can be viewed by clicking on the cover. Most modern-day brochures, however, are cover only (denoted by a white caption) due to photograph copyrights. These items are historical in scope and are intended for educational purposes only; they are not meant as an aid for travel planning. The dates under each brochure do not reflect the complete range of years that a particular brochure was issued.

1974	1976	1978	1982	1987	1988
1990	cover only 1992
1993-2005		cover only 2007-2018		cover only 2020

Adeline Hornbek: Overcoming Challenges Date Unknown		Climate Change Date Unknown		Climate Change 2023
Fossil Insects Date Unknown		Fossil Insects 2023		Fossil Plants Date Unknown
Fossil Plants 2023		Fossil Vertebrates Date Unknown		Fossil Vertebrates 2023
Geologic Trail Date Unknown		Geologic Trail 2023		Hiking Trail Map Date Unknown
Hiking Trail Map Summer 2020		Hiking Trail Map Fall 2021		Hiking Trail Map Summer 2023
History of the Florissant Fossil Beds Date Unknown		History of Science and Land Use 2017		History of Science and Land Use 2023
Geoheritage 2023		Geologic History of Lake Florissant Date Unknown		Geologic History of Lake Florissant 2023
Geologic Beginnings of Lake Florissant Date Unknown		Microscopic World of Florissant Date Unknown		Microscopic World of Florissant 2023
Paleontology Program Date Unknown		Paleontology Program 2023		Petrified Forest Date Unknown
Petrified Forest 2023		Road Guide to Florissant's Volcanic Past 2017		Road Guide to Florissant's Volcanic Past 2023
Date Unknown
Colorado Petrified Forest and Guest Ranch Date Unknown	Colorado Petrified Forest 1956	Colorado Petrified Forest c1960s	Your Souvenir Forest Guide of the Colorado Petrified Forest c1960s	Colorado Petrified Forest Date Unknown	Colorado Petrified Forest Date Unknown
Pike Petrified Forest 1956	Pike Petrified Forest Date Unknown	Henderson Petrified Forest Date Unknown

A Fossil Leaf-Cutting Bee (T.D.A. Cockerell, extract from The Canadian Entomologist, Vol. 40 No. 1, January 1908)

Fossil Flora and Stratigraphy of the Florissant Formation, Colorado (Emmett Evanoff, Kathryn M. Gregory-Wodzicki and Kirk R. Johnson, eds., Proceedings of the Denver Museum of Nature & Science, Series 4 No. 1, October 1, 2001, ©Denver Museum of Science & Nature, all rights reserved)

New Miocene Coleoptera from Florissant (H.F. Wickham, extract from Bulletin of the Museum of Comparative Zoölogy at Harvard College, Vol. LVIII no. 11 December 1914)

The following visual bibliography is just a sampling of the handbooks and books which have been published for this park. NPSHistory.com does not endorse these, but are merely presenting them for informational purposes only. As most are copyrighted, we are only able to provide the covers, and not contents, of these publications.

cover only

1982

cover only

The Fossils of Florissant
Herbert W. Meyer
2003

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Saved in Time: The Fight to Establish Florissant Fossil Beds National Monument, Colorado
Estella B. Leopold and Herbert W. Meyer
2012