Great Lakes and St. Lawrence Lowlands
The southern parts of Quebec and Ontario, in the section of the Great Lakes (bordered entirely by Ontario on the Canadian side) and St. Lawrence basin (often called St. Lawrence Lowlands), is another particularly rich sedimentary plain. Prior to its colonization and heavy urban sprawl of the 20th century, this Eastern Great Lakes lowland forests area was home to large mixed forests covering a mostly flat area of land between the Appalachian Mountains and the Canadian Shield. Most of this forest has been cut down through agriculture and logging operations, but the remaining forests are for the most part heavily protected. In this part of Canada the Gulf of St. Lawrence is one of the world's largest estuary (see Gulf of St. Lawrence lowland forests).While the relief of these lowlands is particularly flat and regular, a group of batholites known as the Monteregian Hills are spread along a mostly regular line across the area. The most notable are Montreal's Mount Royal and Mont Saint-Hilaire. These hills are known for a great richness in precious minerals.