Known as Yeager Rock, this large basalt erratic was ice-rafted by
the 4,000-foot thick Cordilleran Glacier and deposited at this
location when the ice melted. The Cordilleran Ice Sheet covered all
of British Columbia and northern Washington State down to Seattle
and Spokane between 15,000 and 12,800 years ago. The Cordilleran
Ice Sheet had three main lobes: The Puget Lobe which scoured out
the Puget Sound, the Okanogan Lobe which blocked the Columbia River
at the site of the present day Grand Coulee Dam forming Glacial
Lake Columbia, and the Purcell Lobe which blocked the Clark Fork
River creating Glacial Lake Missoula.
Named for a pioneer family that settled in this area in 1890,
this 400-ton, three story high erratic is one of the more
spectacular erratics that are strewn about the landscape.
While in the area be sure to visit Split Rock, another fanatic
erratic located 1.1 miles west on SR 172 from Yeager Rock. Split
Rock is so-named due to ice-wedging that has completely split this
erratic in two.