- A glacial erratic is a glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from the Latin word errare (“to wander”), are carried by glacial ice, often over distances of hundreds of kilometres. Erratics can range in size from pebbles to large boulders such as Big Rock (16,500 tonnes or 18,200 short tons) in Alberta.
- 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.
