A remarkable volcanic belt begins in southern Alaska at the head of Cook Inlet, and follows the coast in a broad southwesterly curve fifteen hundred miles long through the Alaskan Peninsula to the end of the Aleutian Islands, nearly enclosing Behring Sea. It is very ancient. Its mainland segment contains a dozen peaks, which are classed as active or latent, and its island segment many other volcanoes. St. Augustine's eruption in 1883 was one of extreme violence. Kugak was active in 1889. Veniaminof's eruption in 1892 ranked with St. Augustine's. Redoubt erupted in 1902, and Katmai, with excessive violence, in June, 1912. The entire belt is alive with volcanic excitement. Pavlof, at the peninsula's end, has been steaming for years, and several others are under expectant scientific observation. Katmai may be outdone at any time. Katmai is a peak of 6,970 feet altitude, on treacherous Shelikof Strait, opposite Kodiak Island. It rises from an inhospitable shore far from steamer routes or other recognized lines of travel. Until it announced itself with a roar which was heard at Juneau, seven hundred and fifty miles away, its very existence was probably unknown except to a few prospectors, fishermen, geographers, and geologists. Earthquakes followed the blast, then followed night of smoke and dust. Darkness lasted sixty hours at Kodiak, a hundred miles away. Dust fell as far as Ketchikan, nine hundred miles away. Fumes were borne on the wind as far as Vancouver Island, fifteen hundred miles away. Weather Bureau reports noted haziness as far away as Virginia during succeeding weeks, and the extraordinary haziness in Europe during the following summer is noted by Doctor C.S. Abbott, Director of the Astrophysical Observatory of the Smithsonian Institution, in connection with this eruption. Nevertheless, Katmai's is by no means the greatest volcanic eruption. Katmai's output of ash was about five cubic miles. Several eruptions have greatly exceeded that in bulk, notably that of Tomboro, in the island of Sumbawa, near Java, in 1815, when more than twenty-eight cubic miles of ash were flung to the winds. Comparison with many great eruptions whose output was principally lava is of course impossible. The scene of this explosion is the national monument of to-day. The hollowed shell of Katmai's summit is a spectacle of wonderment and grandeur. Robert F. Griggs, who headed the expeditions which explored it, states that the area of the crater is 8.4 square miles, measured along the highest point of the rim. The abyss is 2.6 miles long, 7.6 miles in circumference, and 4.2 square miles in area. A lake has formed within it which is 1.4 miles long and nine-tenths of a mile wide. Its depth is unknown. The precipice from the lake to the highest point of the rim measures thirty-seven hundred feet.