Lemei Rock is one of the many shield volcanoes topped by cinder cones and spatter cones that make up the Indian Heaven volcanic field. About 60 eruptive centers lie on the long, N10°E-trending, Indian Heaven fissure zone. The field has a volume of about and forms the western part of a Quaternary basalt field in the southern Washington Cascades, including the King Mountain fissure zone along which Mount Adams was built.