Covering more than half of Canada, it also includes most of Greenland and extends into the United States as the Adirondack Mts. The first part of North America to be permanently elevated above sea level, it has remained almost wholly untouched by successive encroachments of the sea upon the continent.
Drainage is generally very poor on the shield.
The southern part of the shield has thick forests while the north is covered with tundra. Licensed from Columbia University Press. All rights reserved.