This is an undescribed fossil fan palm--possibly related to the living Carnauba wax palm native to the moist valleys of Brazil--preserved on a chunk of organic-rich mudstone of the Middle Eocene Ione Formation. What you're looking is but a portion of what would have been the "fan" part of the palm in actual life. The roughly 45 million-year-old specimen came from an extraordinarily rich locality on private property in Amador County--a specific site currently under formal paleobotanical study by Dr. Jack A. Wolfe (retired member of the United States Geological Survey) and Howard E. Schorn (retired Collections Manager of Fossil Plants at the University California Museum of Paleontology in Berkeley), among others, who hope to use the fossils to help approximate the paleoelevation of the ancestral Sierra Nevada region during the geologic past.

Please note: All fossil localities in the Ione Formation of Amador County, California, presently occur on private property; explicit permission from the land owners must be secured before collecting fossils there.