A photo of Mount Scott

This view shows more detail of Mount Scott (a stratovolcano), Sentinel Rock and Skull Rock (the remnant of lava flows). The massive volcano, Mount Mazama, was built up from eruptions of lava flows, ash, and cinder. In general, rocks solidified from lava flows and volcanic stocks are more resistant to forces of erosion and mass wasting than ash and cinder beds. As a result, remnants of ancient lava flows typically form the high, dark, shear cliffs around Crater Lake, whereas the ash and cinder layers generally form the steep slopes around the lake. Many lava flows, such as at Sentinel Rock, flowed down ancient glaciated valleys that formed on the side of Mount Mazama between eruptions (USGS, 2005).