From the Bench: Preservation Project Protects 65 Million-Year-Old Fossilized Leaves for Scientific Study

This post is part of the “From the Bench” series celebrating the work of conservators. Part scientist, part detective, they work to preserve the past for the future. This series features the voices of conservators who are working on IMLS-supported projects in museums across the United States. For more information about IMLS funding for museums see

By Jude Southward, Conservator and Museum Conservation, Department Chair
Denver Museum of Nature and Science

It’s fall, and the trees are shedding their leaves, making playful swirls on the ground. Have you ever wondered what happened to leaves that fell to the ground around 65 million years ago? At the Denver Museum of Nature & Science (DMNS), we are rehousing beautiful fossil leaf specimens from Denver Basin excavations that date from that time period. The specimens are remarkable because so many of them retain a cuticle. The cuticle is the waxy protective coating on living leaves, and it allows researchers to investigate past carbon dioxide levels. It is just one of the ways the museum is helping to study our changing climate.

Leaf with intact compression-impression macro fossil and cuticle showing excellent preservation of the leaf detail

With help from a Conservation Project Support grant from IMLS, DMNS is providing optimum storage conditions for the 8,900 fossil leaf specimens housed at DMNS. The leaf fossils are preserved on mud, silt, and clay matrices that are not strongly cemented together.  Even though these are fossil specimens, they are prone to damage from handling or from prolonged exposure to water, which could occur during fire suppression.  If the cementation fails, the fossil breaks apart. This project is helping us protect these specimens against both physical and water damage. Many museum staff members are working on the project including conservators, curators, collections managers, and a dedicated crew of volunteers in the museum’s Earth Sciences Department. The team is working together to place the specimens in standard trays with customized supports. The specimens and their trays will then being placed in new, high-quality, closed cabinets.

As part of the project, staff conservators are completing condition reports on the 800 type specimens in the collection. These type specimens are the most significant taxonomic fossil leaves in our collection because they are the specimen on which a new species description is based. They have the highest curatorial and conservation priorities for closer examination, which allows us to see the remarkable structure of the leaves.

In addition to the rehousing and condition reporting by conservators, the effort entails work by project staff to conduct collection management activities, such as reviewing taxonomy to determine correct storage location, inventorying specimens, and creating storage labels. Finally, all inventory and condition report information is being entered into the collections database.

I have had the opportunity to work on more than a dozen IMLS-funded projects. I truly appreciate the impact of the agency’s commitment to collections preservation.