I.

Introduction

Canadian Shield or Laurentian Plateau, vast horseshoe-shaped geological region that covers central and eastern Canada and small parts of the northern United States. The shield extends in a great semi-circle around Hudson Bay, ranging from the Arctic coast north of Great Bear Lake in the Northwest Territories to northern Quebec and Labrador. It covers about 4.8 million sq km (1.9 million sq mi) and occupies almost one-half of Canada's total area, including portions of six provinces (Newfoundland and Labrador, Quebec, Ontario, Manitoba, Saskatchewan, and Alberta) and two territories (Northwest Territories and Nunavut). In the United States it includes the Superior Upland of northern Minnesota, northern Wisconsin, northern Michigan, and the Adirondack Mountains of north-eastern New York.