Continental shields are large, stable areas of the Earth's crust that are primarily composed of ancient rocks. These regions are typically found in the interiors of continents and are characterized by their flat terrain and low relief. They often contain valuable mineral resources, such as gold, copper, and iron, making them important for mining activities. These shields are formed from the remnants of ancient mountain ranges and tectonic activity. They are usually surrounded by younger sedimentary basins and are significant in understanding the geological history of the Earth. Examples of continental shields include the Canadian Shield and the Baltic Shield.