My first real adventure into the Rocky Mountains was to visit Florissant Fossil Beds National Monument. The drive to get here from Colorado Springs is easy compared to some other mountain passes I have been through. Temperatures are definitely dropping compared to lower elevations but I have no complaints about that – finally, it feels like autumn to me for the first time all year.
Logically I started at the visitor center to learn more about why this site exists and it’s significance.
No surprise, the big attraction are the fossil formations. Dating back 34 million years ago near the end of the Eocene where the climate began to cool, geologic uplift was changing the mountain landscape, and volcanic eruptions from surrounding calderas created conditions where life was preserved in fossils of plant and insect life. Florissant was actually a lake during this time, and the ash falling in the waters combined with the clays, soils, and minerals to preserve this life in great detail.
Some of the tree life can be seen here including oaks, cedars, pines, and spruces which adapted into the modern era. There are also samples of extinct beech and birch variants. Indeed one of the most useful findings are the plant fossils and leaves which help understand the climate of that era and give us insights into our own time period.
Continuing down the display are legumes, fruits, cattails, and roses.
Elm, currant, hydrangea, and hickory (amongst others) round out the main display case.
The next section has animal life including bowfin fish, spiders, earwigs, flys, damselfly, and lanternfly. Some of these specimens help us understand what the environment of the area was like in that time period. From what I remember the area would have been a shallow fresh-water lake as several of these insects would only be found in such conditions.
Continuing on: midges, crane fly, robbery fly, ants, moths, and more.
Other displays focus on the fossilized trees and tying things together to understand how the climate was changing in that time period. We will see more of the trees in my next post covering the loop hike outside the visitor center.
Another display explaining how the scientific method of reviewing and re-checking previous findings continues to bring new discoveries; how identifying tsetse flies (when they are only currently found in tropical sub-Saharan Africa) raises questions about how widespread insects were across the world; and how Florissant has more known fossil butterflies than anywhere in the world.
And another fine display showing how the fossils came to be: in short, large animal skeletons and Redwood tree bases were permineralized (filled with minerals), volcanic ash and mudflows filled the valley and dammed up the stream which created the lake, animal and plant life fell into the lake, and then ash and diatoms created the paper shale which encased the life forms and captured the fossils in layers.
If you have time I strongly suggest watching the educational film in the small theater which explains the history in much greater detail than I ever could in a simple blog post.
OK now class is dismissed and it’s time to head outdoors. Next up is the fossilized Redwood stumps in the old lake bed.
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