The Canadian Shield, also called the Laurentian Plateau, or Bouclier canadien (French), is a large area of exposed Precambrian igneous and high-grade metamorphic rocks (geological shield) that forms the ancient geological core of the North American continent (the North American Craton or Laurentia). Composed of igneous rock resulting from its long volcanic history, the area is covered by a thin layer of soil. With a deep, common, joined bedrock region in eastern and central Canada, it stretches north from the Great Lakes to the Arctic Ocean, covering over half of Canada; it also extends south into the northern reaches of the United States. Human population is sparse, and industrial development is minimal, while mining is prevalent.