Glacial Terraces

About 20,000 years ago Ontario was covered by a great glacier, the fourth glaciation in this region within the past million years. The meltwaters from these gigantic ice-sheets filled the Lake Superior basin and progressively developed new drainage patterns which gradually lowered the level of the lake. As the waters receded from old shorelines more recent lake deposits where exposed and new shorelines established. This process produced a succession of terraces, separated from one another by escarpments or shore cliffs formed by wave erosion. Flat terraces, composed mainly of sand and gravel deposits, are found at various places around the Lake Superior shoreline and their prominence gave Terrace Bay its name.

Plaque via Alan L. Brown's site Ontario Plaques. Full page here.

• toronto
• ontario
• alan brown