 The weight of the ice depressed the crust so that, when the ice retreated (melted), the Atlantic Ocean waters invaded to form the Champlain Sea (and deposit the most recent sediments of sand, gravel, and clay).The subsequent rebound of the crust and erosion produced the landscape we see today.Because of its advantageous route, the Sainte-Anne-du-Nord River was widely used by loggers at the start of the 20th century.