THE GÜEAT EÜüPTION Ol' SAKUEA-JIMA IN 1914. 37 



diiimeter üf 650 in. by 450 m. tiiul n depth of 250 m.,^^ eucireled with 

 SI sharp ridge of pitch-black andésite, sometimes rusty browu. It is 

 lx)imded inside with precipitous chffs, so that no one can reach the 

 bottom, where twenty or thiiiy years ago a pond existed which is noAV 

 entirely dry. On the southwest and north chffs, built up of mud breccia 

 mixed with pumice, capped with tabular or columnar solid lava, sulphurous 

 fumes issue but not violently. 



Gulch About 500 m. landward from the shore near Yuno- 



hama at the southern foot of Minami-daké, there is a spot where 

 steam and carbonic acid mixed with sulphur dioxide issue from 

 tlie bottom of a dry ravine. Insects and birds and even men 

 were asphyxiated on approaching the aperture of the mofette. 

 The place is called by the people Dokudani or ' poison gulch.' 



The form of the narrow lava-conduit of whole Sakura-jima 

 PoLYAxiAL js what F. V. Wolft' styles the ' polyaxial central type.' 



Type rpj^^ ^^^^^ apical advcutive pit-craters, the middle and 

 southern, are only accidentally formed Ijy l)ranchings of the 

 principal canal, as may be surmised by an inspection of the 

 annexed Geologic Map. 



The linear compound volcano so formed has attained roughly 

 a maximal height of 1,000 ??z., which is, tJie icriter believes, the 

 average height of modem volcanoes in Japan, corresponding to the 

 size of the konide, the nature of the magma of intermediate 

 acidity, and the amount of energy of the magma reservoir which 

 is usually assumed to lie under 1,000?». from the ventholes. 



Topo- TopoGEAPHic FEATURES. — From the mode of for- 



GKAPHIC 



Featuke mation as well as from the material which built up 

 Sakura-jima, we are able to recognize the topographic form of 



1) The maximum depth of the crater-bottom of other andesite-Tolciinoes of Jaimu seems 

 to the writer to be 250 to 300 w., without the danSer of disruption of the boily of a volcano. 



