Boot HillEarly Middle Eocene Republic flora from northeastern Washington state

Eocene deposits of the Klondike Mountain Formation near the town of Republic, Washington host a number of small lacustrine fossil localities that have produced a wealth of plant, insect and fish fossils. The main fossiliferous locality is known as Boot Hill, located on city property in the town of Republic and administered by the Stonerose Interpretive Center ( Over the years, this site has produced many significant specimens that have widened our understanding of the Eocene epoch in the northwest of North America. In addition to the Boot Hill site, there are several other localities in the formation that have produced important specimens. Significant collections of Republic area fossils are housed at the Stonerose Center in Republic, the Burke Museum at the University of Washington, and the Denver Museum of Nature and Science.

The Republic deposits are part of the larger Okanagan Highlands localities, a series of Eocene lakebed deposits that extend from Republic up into central British Columbia. These sites are believed to represent a relatively cool upland habitat that provide a window into the early development of the mixed mesophytic and temperate broadleaf forests that are widespread in modern day eastern Asia and eastern North America.