The Geographical situation and ecological character of the Aleutian Islands are of such nature as to give the archaeological record there special significance with regard to certain problems of Eskimo prehistory. From the point of origin, Unimak Island, the islands extend to the west in a thousand mile long chain which is essentially a broken extension of the Alaska Peninsula. Water gaps are relatively short in the eastern section, although the inter-island passes are often perilous because of currents and tide rips, not to speak of frequent fogs and strong winds. In the west the water gaps tend to become longer, culminating in the 40 miles or more of stormy open water involved in the passage from the Rat Islands to the Near Islands. Between the westernmost of the Aleutians, Attu Island, and the Russian Commander Islands is a still more formidable gap of about 250 statute miles, and 138 statute miles intervene between the Commander Islands and the coast of Kamchatka. Since there is no reason to think that these geographical conditions were significantly different in the appreciably recent past, the inference clearly seems to be that the Aleutian Islands were peopled from the Alaska Peninsula by competent boatmen.