Station 11: Sliding Boulders and Glacial Erratics

The deep uphill groove and the mound of dirt in front (downhill side) indicate that this huge boulder has slid downhill. Did it happen all at once or was it a gradual process during freeze/thaw cycles? This huge boulder was transported by glaciers and left on the hillside as the ice melted. Stones transported by glaciers are called glacial erratics.