Airport Boulder, at Martha Lake Airport Park in Martha Lake, said to be “one of the largest glacial erratic boulders in urban King, Snohomish, and Pierce counties”, is approximately 20 feet (6.1 m) long on its longest axis and about twice a man’s height. The erratic is composed of greenstone, and has long been used for bouldering (rock climbing), with at least four ascent routes.
Glacial erratic boulders of Snohomish County, Washington (Wikipedia) Glacial erratic boulders of Snohomish County are large glacial erratic boulders of rock which were moved to Snohomish County, Washington by glacial action during previous ice ages.
