This 35-acre site, located on a glacial outwash plain, preserves an example of the "mima mound" landscape, and a small remnant of native Puget prairie grassland, which is dotted with large glacial cobbles.  The landscape is a gently rolling plain with low swales and rises.  The largest known population of a Federal-listed Threatened species occurs on the preserve. A state Sensitive plant species which occurs only in Puget prairies, white topped aster, is also protected on the preserve.  (Thurston County)