Southeast Caldera Wall 8. View of southeast caldera wall (Panoramas J and K) from southwest shore of Crater Lake. Mount Scott is on the skyline at left, Kerr Notch in center, and Sun Notch at right. The notches are glacial valleys that were beheaded when the caldera collapsed during the climactic eruption ~7,700 yr ago. Dutton Cliff, between the notches, and the notch walls expose andesite of Applegate Peak (unit aa; ca. 210-270 ka). Andesite of Kerr Notch (unit ak; ~300-340 ka), dacite of Chaski Bay (unit db; ~350-380 ka), and andesite of phantom cone (unit apn; 403±12 ka) are exposed on either side of the talus below Dutton Cliff. Andesite of phantom cone is the oldest unit exposed in the caldera walls above lake level. Photograph by Charles R. Bacon.