152 



OBSERVATIONS AND RESULTS IN PHYSICAL OCEANOGRAPHY 



Soundings 934 and 935 require the introduction in 

 Fleming Deepofan 8000-meter contour, and the extension 

 of the 6000- and 7000-meter lines in this vicinity. South 

 of Fleming Deep sounding 930 shows an isolated peak, 

 and to the north of Fleming Deep another isolated peak 

 is evidenced by sounding 944. 



Near the southern end of Tuscarora Deep the east- 

 ern 6000-meter line must be moved somewhat more to 

 the east to conform to soundings 948 and 949, whereas 

 farther north sounding 959, on the western slope of the 

 deep, requires the 7000-meter line to be moved to the 

 eastward. East of Tokio soundings 965 and 966 show 

 that the 2000-meter contour and probably the 3000- 

 meter line need to be moved eastward. 



Somewhat farther north and on the eastern slope of 

 Tuscarora Deep, soundings 972 to 977 inclusive intro- 

 duce an S-shaped irregularity into both the 6000- and 

 7000-meter lines and diminish the area enclosed in the 

 8000-meter contour. 



Soundings 1021 to 1048 inclusive, of which nos. 1022, 

 1026, 1027, 1032, 1033, 1043, and 1047 are greater than 

 6000 meters, suggest that a 6000-meter contour runs 

 along the 47th parallel from about longitudes 165" to 175° 

 east, and that this represents the southern boundary of 

 a connection between the Kamchatka Trench and the 

 Aleutian Deep. Soundings taken by the U. S. S. Ramapo 

 have been published by the U. S. Hydrographic Office in 

 a "List of oceanic depths 1931, North Pacific Ocean," 

 H. O. no. 210a, Washington, 1932. Soundings listed in 

 this publication as "route no. 8," on pages 4 to 12 in- 

 clusive, parallel the route of the Carnegie somewhat to 

 the southward between Japan and San Francisco. As pub- 

 lished, they are based on a constant sounding velocity of 

 1463 meters per second. Those soundings between lati- 

 tude 34° or north, longitude 140° 41' east, and San Fran^ 

 Cisco have been corrected for sounding velocity accord- 

 ing to the Carnegie data. Comparing these soundings 

 with the Carnegie soundings, there seems to be a low 

 rise on the seaward side of Tuscarora Deep, Kamchatka 

 Trench, and Aleutian Deep, separating these from the 

 deep basin of the North Pacific. A submarine mountain on 

 this rise is disclosed by soundings 1029, 1030, and 1031, 

 with another such mountain indicated by sounding 1038. 



Referring once more to the Monaco chart, it would 

 seem from soundings 1050 to 1062 inclusive, of which 

 nos. 1050, 1061, and 1062 are less than 5000 meters, that 

 the 5000 -meter contour borders the southern part of the 

 Aleutian Deep as far westward as about longitude 177° 

 west before it turns southeastward. 



One other notable departure from conditions indicat- 

 ed on the charts has yet to be considered. This is a wire 

 sounding of 1344 ± 40 meters at oceanographic station 40 

 in latitude 1° 32' south and longitude 82° 16' west. This 

 was named Carnegie Ridge, but in the absence of other 

 soundings we can only remark that it occurs in an area 

 where the chart shows a depth of between 3000 and 4000 

 meters. 



The names "Carnegie Ridge," "Merriam Ridge," 

 "Bauer Deep," "Fleming Deep," and "Hayes Peak," 

 assigned by Captain J. P. Ault to these various features 

 at the time of their discovery, have been retained in this 

 discussion along with the name "Ault Peak," which was 

 christened after Captain Ault's death. 



Some of the profiles of approach to land in the Pacific 

 are shown in the accompanying diagram (fig. 1). These 

 are all islands and are, therefore, shown along with the 

 maximum slope which is theoretically stable according 

 to Littlehales (Bull. Nat. Res. Council, no. 17, pp. 90-93, 

 1922). Inasmuch as some of the.se islands have an ap- 

 preciable mass above the water level, a strict compari- 

 son is not justifiable. In order to better compare the 

 actual bottom slopes, all the curves have been started 

 from the shore line and the distance of the center of the 

 peak from the shore line has been given in tabular form 

 to enable the reader to differentiate between the large 

 and small islands. Of the nine islands, the approaches 

 for which are shown, four are grouped as large and five 

 as small. An interesting feature which offers food for 

 thought is that four of the five small islands shown have 

 a secondary ridge or elevated prominence on their north- 

 eastern sides, whereas the fifth (Wake Island) was not 

 approached from this direction. In the case of Penrhyn 

 Island, this ridge apparently comes very close to the 

 surface and is known as Flying Venus Reef. The data 

 are, of course, too meager for conclusions, and the ab- 

 sence of similar ridges on the other sides of these is- 

 lands, as indicated by the Carnegie soundings, may be 

 owing to too great an interval between soundings, rather 

 than to the actual nonexistence of such irregularities. 

 In the case of Amanu Island, the apparent irregularity 

 may not be real and may only be the result of the devious 

 path of approach. 



These findings, as well as the entire sounding pro- 

 gram of the Carnegie , stress the need of more thorough 

 exploration of the ocean depths and impress one with the 

 inadequacy of our present knowledge of the bottom fea- 

 tures. 



