94 S. SEKIYA AND Y. KIKUCHI 



direction — the Kitakaini from north to south, and the Abukuma from 

 south to north — and along which passes the chief highway of Japan. 

 The valleys separate the Abukuma and Kitakami ranges from a high 

 ridge which, traversing the middle of Northern Japan, forms struc- 

 turally the backbone of the region, and constitutes the main water- 

 shed between the Pacific Ocean and the Japan Sea. This central ridge 

 owes its origin to volcanic effusions of comparatively younger date, 

 and consequently the natural barrier thus created is made up mostly of 

 prominent volcanic peaks, and differs in its features from the neighbour- 

 ing old land. The more important of the volcanic peaks are, Osore- 

 yama and Yake-yama on the extreme north of the main island, and 

 thereafter Gaiiju-san, Komaga-take (Province of Rikuchü), Zoô-zan, 

 AzLima-san, Bandai-san, Nasu-dake, Shirane-san (Province of Shimo- 

 tsuke), Akagi-san, &c. These mark the course of the line of weakness 

 along which terrestrial disturbances of varying degree have manifested 

 themselves, in times past, attaining their climax during the Tertiary 

 Era, and thereafter declining into their present state of comparative 

 quiescence. 



Bandai-san (Lat. 37° 30' N., Long. 140° 6' E.) is situated in the 

 Yama District (kört) in the Province of Iwashiro, immediately adja- 

 cent to the Abukuma mountain region, a part of which, formed of 

 granite and gneiss, borders the east bank of the river Nagase that runs 

 immediately past the foot of the volcano. Besides Bandai-san, there 

 are in this part of the country several other volcanoes, both active 

 and extinct, as shown in PI. XXIA"; the line of principal volcanoes 

 belonging to the central ridge of Northern Japan, already referred to, 

 is shown in the same Plate by a broken line. On the north-east of 

 Bandai-san are Dake-yama and the Azuma-san group, the latter con- 

 sisting of three principal peaks called the Eastern, Western and Mid- 

 dle Azuma: while on the south are Nasu-dake, Takahara-yama, &c. 



