From Wood and Kienle (1990): The "Morzhovoi Volcanics constitute a late Pliocene to early
Pleistocene basaltic and
andesitic stratovolcano. Volcanism culminated in the formation of a large collapsed
crater. Though presently ice-free, extensive Pleistocene glaciation has eroded most original stratovolcano features, including the actual crater rim, leaving long U-shaped valleys." From Myers (1994): "The oldest
volcano [of the Cold Bay Volcanic Complex] Morzhovoi Volcano, is of late Tertiary to
Quaternary age, lies on the southern edge of the Alaska Peninsula, and consists of basalts, andesites, and associated
pyroclastic rocks (the Morzhovoi Volcanic Series). Because it has undergone extensive erosion, only remnants of the volcano remain. Isolated peaks, e.g. North and South Walrus Peaks, that are fragments of the original
caldera rim range in height from 797 to 893 m."