Big Rock, once known as the Rock of Ages, is a 30-foot (9.1 m) high greenstone erratic and a landmark on Main Street in Coupeville, at one time considered for a city conservation easement.
https://github.com/davepinch/pinchy.cc/blob/master/content/topics/places/glacial-erratics/erratics/big-rock-coupeville/big-rock-coupeville.md