From Smithsonian Institution, online database, accessed December 8, 2003: "Mount Denison lies near the head of the Serpent Tongue, Hook, and Hallo glaciers NE of Snowy
volcano. This poorly known section of Katmai National Park contains a cluster of four closely spaced and mostly ice-covered vents. Mount Denison lies at the SW end of this volcanic chain, which also includes Steller, Kukak, and Devils Desk volcanoes. Orientation of
lava flows and a thick cross-bedded
tephra deposit suggest that a
vent is located near Mount Denison (Swanson, in Wood and Kienle 1990). The precise age of the most recent activity at Denison is not known, but the volcano was considered to have been active during the
Holocene (Nye et al., 1998)."