Carya washingtonensis facts for kids

Carya washingtonensis is an extinct type of hickory nut. It belongs to the walnut family, called Juglandaceae. We only know about this ancient nut from Miocene rocks found in Kittitas County, near Ellensburg, Washington.

Where These Ancient Nuts Were Found

The first Carya washingtonensis nuts were found in a place called Badger Pocket-Squaw Creek. This area is south of Ellensburg, in Washington state. Today, this spot is part of the Yakima Training Center.

The rocks where these nuts were found are very old. They are part of the Ginkgo Flow basalts. These rocks are famous for fossils found at Ginkgo Petrified Forest State Park. The Ginkgo Flow is about 15.6 million years old. This time period is called the Miocene epoch.

The nuts were first found in the 1940s by Carl Clinesmith. He discovered a large group of over fifty nuts. They were all stuck together in a petrified Platanus (sycamore) tree stump. These nuts had turned into rock, a process called silicification.

For a while, this amazing group of nuts was lost. But in 1995, it was reported to be on display. You can still see parts of it today. It is kept at the Burke Museum of Natural History and Culture in Seattle, Washington.

How Carya Washingtonensis Was Studied

The Carya washingtonensis species was officially described using three special nut specimens. One is called the holotype, and the other two are paratypes. These specimens are like the main examples for the species.

Most of these important nuts are kept at Harvard University. Another one is at Indiana University.

A paleobotanist (a scientist who studies ancient plants) named Steven R. Manchester studied these nuts. He wrote about them for his PhD. In 1987, he officially published his description of C. washingtonensis. He named the species washingtonensis because it was found only in Washington state.

What the Nuts Looked Like

The nuts of Carya washingtonensis were round. Their surface was mostly smooth, but some had slight wrinkles. They had four faint angles at the top.

These nuts were about 18 to 20 millimeters (0.7 to 0.8 inches) long. They were 14 to 19 millimeters (0.5 to 0.7 inches) wide. Some nuts were so well preserved that scientists could see inside them. The nut wall was about 1.5 millimeters (0.06 inches) thick.

When Steven Manchester first studied the large group of nuts, he thought it was a rodent's food stash. It looked like an ancient squirrel or other animal had collected them. At that time, it was the oldest known animal food cache ever found. Since then, an even older one was found in Germany. That cache of Castanopsis fruits was found in a sand dune.