THE ERUPTION OF BANDAI-SAN. 95 



Immediately north-west of Bandai-san there is a small lake called 

 Okuni-numa, at an elevation of 1065 m. above the sea-level, and 

 surrounded on all sides by ridges, the highest of which is called 

 Nekoma-yama, and rises 305 m. above the lake. Judging from its 

 features, Okuni-numa is unquestionably an old crater. Between it 

 and Bandai-san there stands a round -topped hill, till lately over- 

 grown with forest, and known as Marumori-yama, which is apparently 

 a small volcanic cone. The few naked tree-trunks, stripped of bran- 

 ches and leaves, that are now to be seen on this hill-top vividly attest 

 the severity of the recent eruption. 



From the fact that the older rocks of the Abukuma mountain- 

 land underlie the volcanic groups in the vicinity of Bandai, it seems 

 reasonable to infer that the volcanoes originated on the fractured 

 edges of the old formation. 



Though all of the volcanoes that have been in eruption in recent 

 times are shown as active on Plate XXI V, it is to be understood that 

 such activity never exceeded intensified solfataric explosions, disturb- 

 ing the upper crust alone. The late explosions of Nasu-dake and Azu- 

 ma-san were of this class only, neither lava nor pumice having been 

 ejected. The extreme volcanic energy which once raged in the district 

 of Bandai seems to have gradually waned down to the present time. 

 Denuding action has evidently played a more prominent part than 

 plutonic agency in changing the forms of the mountains, and the 

 decomposition of the rocks has produced a thick layer of soil, sup- 

 porting a dense forest-growth, and concealing the old lava-flows and 

 scoriaceous ejections which attest the volcanic origin of the hill-mass- 

 es. Peasants worked daily among the green forests of Bandai, to 

 collect fuel and to fell trees, wholly unsuspicious of the calamity that 

 hung over them. 



The district about Bandai-san is made up principally of tufa- 



