The Valley Overlook · National Park Service
Geoheritage Highlight! The natural beauty of landscapes links us to Geoheritage and causes us to wonder how these landscapes formed. From this high vantage point, you can visualize how the Florissant valley has changed through geologic time and wonder about its future This location offers a panoramic view across the Monument’s main valley and to the distant mountains beyond. The valley was once covered by a forest with about 150 different species of trees and shrubs now preserved as fossils. Tall redwoods formed the Eocene forest canopy, and many kinds of hardwood trees grew in the forest understory. Today’s sparse montane conifer forest has far fewer species and consists mostly of pines and spruce with scattered aspens and several kinds of shrubs. This change in the forest over geologic time provides clues for big changes in climate too, as there was a major cooling of temperature during the past 34 million years. Not all of the mountains on the horizon were present during the Eocene, yet one of the tall geologic features of that time was the Guffey volcano, which later eroded away, now leaving only traces of its past. .
Valley Today Looking west from a hill across the valley, it is possible to imagine the lake that once filled it and left behind the fossil-rich shale deposits. Today, the only water running through the valley is Grape Creek, a northward-flowing waterway. In the distant past, water within the valley flowed southward, but as the area was tilted through mountain building processes, the direction of waterflow changed.
Eocene Lake During the Eocene, 34.07 million years ago, the valley was much warmer than today. A stratovolcano towered on the horizon 18 miles southwest of the valley. Now mostly lost to erosion, this volcano once had a major impact on the geologic history of the valley and the formation of Florissant's fossils.