Great Lakes and the St. Lawrence River

Geologists tell us that the Great Lakes and the St. Lawrence River were created eons ago, by a combination of deep underground plate movements and glacial activity. The eastern most lakes, Erie and Ontario, along with the St. Lawrence River, are thought to be mostly formed by glacial movement. Imagine a wall of ice and snow, hundreds of feet high, grinding its way down to half past New Jersey, then slowly retreating north, melting along the way. That glacier carved out the 1000 Islands, some large and some very small. It also left shoals. They are nowhere and everywhere, none exactly the same, and all can be dangerous.