Charts. Illana Bay, Eastern part of, Mindanao, southwest coast, P. I., including Polloc Harbor and mouth of Mindanao River, from Spanish surveys to 1888, military maps, and other information, scale 1:100,000; with insets, Polloc Harbor, from survey by U. S. Navy in 1902, scale 1:40,000; Mindanao River, north entrance, from sketch survey in 1900, scale 1:20,000; chart 4619.