Polished and Striated Mud Surfaces in the St. Lawrence Tidal Flats, Quebec

Drift ice polishes and striates the surface of mud tidal flats along the St. Lawrence Estuary. Drag marks are due to tidal currents dragging ice cakes on the bottom. Striated and polished mud surfaces can be fossilized and preserved. If found in consolidated sedimentary rocks, they would be indicators of: the top of a bed, current direction, shallow water, and a cold environment.