TOPOGKAPHY OF THE SAGAMI SEA. 7 



On the chart (PL XIV), which I have prepared taking as 

 basis the L^test hydrographic charts published by the I. J. 

 Navy,"'' I have put down the 10 to 500 fathoin-lines along the 

 coast as well as could be done. The oOO fathom-line is reached 

 at a distance from the shore varying at different places from 

 4Y2 to 20 kilometers. The deepest soundings recorded are from 

 two isolated spots in Sagami Bay. The one, 908 fathoms deep 

 and known to fishermen under the name of SuribacM, is situated 

 oidy .5 kilometers to the south of the mouth of Banyu Rivei-. 

 Just 10 kilometers farther south lies the other spot, 970 fathoms 

 in deptli and known as Umanohura. Both appear to be crater- 

 like depressions surrounded on all sides by shallower waters. 



To judge from what few soundings Ave have, the Central 

 Basin of the Sagami Sea seems to present quite an uneven 

 bottom, ranging from 400 to 700 fathoms and more in depth 

 at different points. Between Tzu and Yries Island, a narrow 

 trough, one point in which gives a sounding of 810 fathoms, 

 probably leads out uninterruptedly into the great ocean basin 

 to the west of the submarine plateau on which the Seven Islands 

 of Izu are situated. On the south-eastern side, the Central Basin 

 seems to be separated from the Gokeba Basin (situated between 

 Cape Mera and Yries Island, presumably sloping down outwards 

 to the abyssal basin of Tusearora) by a bottom much disturbed 

 by submarine elevations that cause considerable shallowness of 

 water in certain places. Tlie most important of these is the 

 submarine ridge known by the name of Okinosc, of which I 

 shall soon speak again. The presence of comparatively shallow 



* For a number of soundings on Okinos^ and neighborhood, which do not stand in 

 the published hydi-ographic charts but liave been given in PI. XIV, I am indebted to 

 the courtesy of Eear-Adtniral KiMOTSKl of the Hydrography, I. J. N., wlio kindly placed 

 them rit uu- disposal. 



