•JTo S. Powers — Volcanic Domex in the Pacific. 



the ollu>r banks. Willi the sudden subsidence of the lake on 

 that dale the liill sank still farther, and the resulting depression 

 mav now be seen on the northeast side of the Ealemaumau pit. 



In December, 1914, a portion of the floor of the Halemau- 

 mau pit rose in a manner similar to the 1894 uplift, but more 

 slowly. The origin may have been the differential loading of 

 other portions of the floor of the pit by fresh flows or it may 

 have been the intrusion of lava beneath. On December 4 with 

 a lake 400 feet long and 150 feet wide, a portion of the floor 

 beneath the main lake and a northeast arm commenced to rise 

 as a crag 300 feet long and 100 feet wide. The relative 

 movements of the crag and of the lake were irregular: in 14 

 days the crag remained 58 feet above the surface of the lake 

 while that body rose 41 feet; in 9 days more (January 2, 

 1915) the lake rose 12 feet but the crag subsided 23 feet; 

 and by March 15 when the lake had subsided 112 feet the crag 

 had sunk only 45 feet. 



A similar crag was formed in September, 1915, between 

 the main lake and a northwest arm. A rectangular block 

 100 feet wide rose about 15 feet, as measured by the writer, 

 between September 9 and 10 while the lake remained stationary 

 except for the daily rises in the late morning and evening. 

 A few days later the lake began to rise and the crag remained 

 above the surface of the lake throughout the rising phase. 



Bogoslof. Six peaks have risen from the sea on top of the 

 submarine Bogoslof volcano since the early navigators explored 

 Bering Sea, about 1768. These peaks have each been composed 

 of solid rock and have probably been formed by the upthrust 

 of viscous magma after the manner of the Mont Pelee spine. 

 Three of the peaks remain and are connected to form one island 

 by the debris from explosions which have destroyed two of 

 the other spines. 



The rise of the first peak, Ship Rock, was reported by the 

 early mariners, and the rock was not washed away until 1888. 

 Old Bogoslof, better known as Castle Rock, was pushed up in 

 179G. Various estimates of the size of this island were made 

 before erosion began to wear it away, and it appears to have 

 been 4,000 feet in diameter and 350 feet in height. There 

 was no summit crater, the top being formed of pinnacles. 

 '.Yew Bogosolf, also called Grewingk and Fire Island, appeared 

 in 1883 as a craterless mass of andesite rising precipitously 

 from the sea to a height of 800 feet. The name Fire Island 

 was applied to the mass for it apparently increased in size by 

 newly upthrust masses for several years with accompanying 

 smoke, steam, and an occasional glow. 



