Volcano Osliima, Idzu. 3 



group of volcanic islands off the Idzii peninsula, commonly called 

 Idzu Shicliitô'\ or the Seven Idzu Islands, and lies in the sea of 

 Sagami'^ about 110 km. S.S.W. of Tokyo, extending over 34^40.5'- 

 47'N. lat. and 139°21'-27.5'E. long. 



The island is nearly elliptic in shape with a length of about 

 15 km. from N.N.W. to S.S.E., a breadth of about 8.5 km. from 

 E.N.E. to W.S.W., and a circumference of about 50 km. It has 

 an area of 103.8 sq. km. and a volume of 22.6 cub. km. (Calculated 

 after Simpson's method.) 



The coast line is simple, being indented only at the inlet of 

 Habu'^ (oe) in the S.S.E. corner. The shore for tlie most part 

 ends abruptly with precipitous cliffs whose elevations vary up to 

 more than a hundred meters. Around the whole coast there are 

 only two sandy beaches of any extent, one on the west, Yuno- 

 hama'^ (Ic), and the other on the south, Sonohama^^ (le). 



The island itself is a gigantic rheuclasmatic volcano elevated 

 755 m. above sea level or about 850 m. above the supposed base 

 on the sea floor. It consists of a central homate called Mihara- 

 yama"' (2c), with an active crater at its summit, and a somraa- 

 separatod by an extensive barren atrio, with such a dreary aspect 

 that it is called " Sabaku "'^ (the desert) by the islanders. 



The ring- wall of the sonmia is incomplete, lacking its north, 

 eastern and soutliwestern sides ; and from both these gaps barren- 

 strips of land extend toward the sea shores. 



The outer slopes of tiie insular volcano vary greatly in differ- 

 ent directions. On the western side, the slope is regular and 

 makes a tine concave curve, the inclination being about 25° near 

 the summit and decreasing uniformly toward the foot; on the 



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