North America has four main natural regions: The Canadian Shield contains a vast area of hard rocks, thousands of lakes, and many rivers. In the south it is covered by dense forest.The Europeans found it hard to cross the Shield. The Appalachians form a chain of old worn-down mountains on the east side of the continent.They are not high, but dense forest and rugged terrain made them difficult to cross. The Western Mountains are a broad system of high mountain ranges and plateaus along the western side of the continent. The Lowlands are found in the central parts of the continent and along the southeast coast.This region is mostly plain. Much of it is good farmland - the type of land that settlers wanted. The St. Lawrence River and the Great Lakes form one of the main entry routes to the continent. People and ships coming across the Atlantic Ocean from Europe can use this route to reach the interior of the continent.The entry route passes between the Canadian Shield to the north and the Appalachians to the south. Other entry routes to the continent include the Hudson River and Hudson's Bay. Do the following questions on Topic 3: Geographic Conditions