The Pleistocene-to-Holocene Indian Heaven volcanic field, located midway between Mount St. Helens and Mount Adams, is an area of low overlapping shield volcanoes with flank vents primarily oriented along a N-S line. Small shield volcanoes topped by cinder and spatter cones dominate the volcanic field, which also contains subglacial vents. The shield volcanoes extend from Sawtooth Mountain on the north to Red Mountain on the south; the high point of the field is 1806-m-high Lemei Rock shield volcano. Basasltic-to-andesitic lava flows blanket much of the field; individual lava flows, many of which display extensive lava tubes, traveled up to 46 km. The youngest eruption about 8200 years ago produced the voluminous Big Lava Bed, a 0.9 cu km basaltic lava flow that traveled nearly 25 km south of its source, an unnamed cinder cone SE of Red Mountain, to within 8 km of the Columbia River.