it is a piece of rock that deviates from the size & type of rock native to the area in which it rests; the name "erratic" is based on the errant location of these boulders. these rocks were carried to their current location by glacial ice, over hundred's of kilometers. Erratics can range in size from pebbles to large boulders such as Big rock which is 16,500 ton is in Alberia.
Glacier-Erratic!
Linear Mode
