Description: Maddren (1919), who visited Akun and Unalaska Islands during August and September 1917, describes the sulfur deposits of Akun Island, near Mt. Gilbert. He reports: "The sulfatara is in rather mild or semidormant activity. Within the smaller area of about 5 acres small volumes of steam and scalding water, accompanied by a small quantity of hydrogen sulphide gas (H2S), issue from fissures at widely spaced intervals, and the remainder of the area shows no particular evidences of the escape of subterranean heat. The most striking evidence of solfatarism is of chemical decomposition of the rock."