There are three main types of volcanoes: 1) Cinder cones erupt small pieces of scoria and pyroclastics that build up around the vent to form cone-shaped hills. Examples include Parícutin in Mexico and Sunset Crater in Arizona. 2) Stratovolcanoes are tall conical mountains composed of layered lava flows and ejecta. Examples include Mt. Fuji in Japan and Mount Vesuvius in Italy. Their explosive eruptions have posed great hazards. 3) Subglacial volcanoes form underneath ice sheets, leaving flat-topped mountains when the ice melts. Good examples are found in Iceland and British Columbia.