Before Crater Lake existed, the massive 12,000-foot Mount Mazama filled the landscape west of Klamath Marsh. A strata-volcano cluster with several vents rather than the more common one or two, it erupted 7,700 years ago and spewed out 12 cubic miles of molten rock, causing the top of the mountain to disappear in a matter of days. The eruption left a large volcanic depression, or caldera, that gradually filled with water to form Crater Lake, the deepest lake in the United States. Mount Mazama's eruption also left a pumice mantle called Mazama Province blanketing 5.1 million acres east of the crest of the Cascade Range, and pumice remains common throughout the Refuge, especially in forested areas where the soil has very little organic matter and is mostly pumice. Archaeologists say Klamath Tribal ancestors lived here during the eruption, and the Klamath People believed the mountain was inhabited by Llao, the god of the underworld; after the mountain destroyed itself, they recounted the event as a great battle between Llao and his rival Skell, the sky god. On the western horizon, 8,934-foot Mount Scott was formed from lava from one of Mount Mazama's vents, and its rock, about 420,000 years old, is among the oldest visible remnants of Mount Mazama.