Florissant Fossil Beds National Monument - http://www.nps.gov/flfo

"When the mountains are overthrown and the seas uplifted, the universe at Florissant flings itself against a gnat and preserves it."-- Dr. Arthur C. Peale, Hayden Expedition Geologist, 1873.
A beautiful mountain valley just west of Pikes Peak holds spectacular remnants of the earth's prehistoric life. Huge petrified redwoods and incredibly detailed fossils of ancient insects and plants reveal a very different Colorado of long ago. Almost 35 million years ago, enormous volcanic eruptions buried the then-lush valley and petrified the redwood trees that grew there. A lake formed in the valley and the fine-grained sediments at its bottom became the final resting-place for thousands of insects and plants. These sediments compacted into layers of shale and preserved the delicate details of these organisms as fossils.