June 20th is National Seashell Day. Since you can’t go collect seashells to celebrate here in Colorado, the museum is going to bring a shell to you! During the mid-Cretaceous period, around 100 million years ago, the Western Interior Seaway began to cover what is now Colorado. This shallow inland sea lasted until the end of the Cretaceous, about 66 million years ago. Due to this, marine fossils are prevalent in Colorado.
This fossil was found near Portland, Colorado and donated to the museum by Charlene Wiener. Inoceramus were bivalves related to living clams and mussels. Sizes could vary from just a few centimeters to 6.5 feet and they were epifaunal, meaning they lived on the seafloor. Inoceramus lived during the late Jurassic through the Cretaceous period before going extinct at the end of the Cretaceous.
The fossil pictured above is currently on display at the Royal Gorge Regional Museum & History Center.
The information presented in this article is compiled using research conducted by the Royal Gorge Regional Museum and History Center.