Wedgwood Rock (Wikipedia) Wedgwood Rock is a glacial erratic (known to geologists as the Wedgwood Erratic) near the neighborhood of Wedgwood in Seattle, Washington. Its mineral composition matches that of Mount Erie, on Fidalgo Island in Skagit County, Washington, 55 mi (89 km) north. Prior to the establishment of the Wedgwood neighborhood, the erratic was known first as Lone Rock and later simply as Big Rock. Transported to its site by the Puget Lobe of the Cordilleran Ice Sheet during the Vashon Glaciation more than 14,000 years ago, it was a landmark for Native Americans in what was once a dense forest.