During the last glacial episode, Tuolumne Meadows was covered by the 2,000-foot thick Tuolumne icefield. Much of this ice moved slowly westward down the Tenaya and Tuolumne River drainages. When the ice encountered a low hill of resistant granite, it overrode the hill and ground the hill into a rounded, streamlined shape, called a roche moutonnée. There are many roche moutonnée in the Tuolumne Meadows area. Two of the best examples are Lembert Dome and Pothole Dome and both are formed from the Cathedral Peak Granodiorite. Pothole Dome has potholes and flutes on the south side of the dome, features that are common in rivers but rarely found on roche moutonnée.