Prehistoric fossils on display at Castle Rock Museum

Visitors to the Castle Rock Museum have no doubt they are stepping back in time. Even the graffiti on the walls shares historic messages.

The museum was once home to the Castle Rock train depot, a place where travelers left their marks on the walls of the depot, chronological tags that date back to 1875.

From now through the fall, another museum display takes visitors back not centuries but eons — 63 million years.

The display is on loan to the museum from Denver’s Museum of Nature and History, caretaker for one of Castle Rock’s most famous finds — fossils from the prehistoric Castle Rock Rainforest Flora.

Museum curators began collecting the fossils, nestled 10 feet under the surface of Castle Rock’s streetscape, about six years ago when work began to widen Interstate 25 near Wolfensberger, said Angie DeLeo, director of the Castle Rock Museum.

Scientists have long known evidence of a prehistoric rainforest lies under the soil between Denver and Castle Rock. The Castle Rock find was unique because it provided proof positive that the ecosystem recovered more quickly from prehistory’s extinction event.

For years, popular theory was that the rainforests took 10 million years to recover from the catastrophic event that wiped dinosaurs from the earth. Radiometric dating at the Castle Rock site confirmed recovery came much sooner.

Palm fronds and plant leaves indicate plant species recovered in about 1.7 million years, said Steve Wallace, staff paleontologist with the Colorado Department of Transportation. Wallace spoke with the News Press in 2008, when he was among a team of scientists who were a fixture at the construction of the Plum Creek Interchange.

The discovery came in mid-July of that year, when the dig disclosed evidence of fossilized palm fronds. The largest of the fronds measured about 4 feet by 5 feet and provided the first evidence of palm trees among the Castle Rock rainforest. They are among 750 plant specimens taken from the Plum Creek site, scientific evidence of a uniquely diverse rainforest.

While the fossils are in the permanent care of the Denver Museum of Nature and Science, DeLeo successfully lobbied for specimens to share with local visitors.

“This is an opportunity for the local folks to see what was dug up,” DeLeo said. “It’s very exciting; this is a great piece of ancient Castle Rock history.”

Entry to the Castle Rock Museum is free. The museum is at 420 Elbert St. in Castle Rock. Hours are noon to 5 p.m. Wednesdays through Fridays and 11 a.m. to 4 p.m. Saturdays.