SOUNDINGS TAKEN DURING THE DISCOVERY INVESTIGATIONS, 1932-1939 73 



ridge again widens and becomes more pronounced, the distance between the 3000 m. contours being 

 approximately 100 miles, as compared with the width of 25 miles at the narrowest part. 



We now come to the most important results of our recent sounding work in the area of the Scotia 

 Sea and Arc ; that is, the determination of some 200 

 miles of the connexion which we believe to exist 

 between the South Sandwich Islands and the South 

 Orkneys. Prior to November 1932, the largest scale 

 British Admiralty chart for this area showed only 

 three soundings of less than 2000 m. (1094 fm.). Early 

 in that year, however, the ' Discovery II ' had obtained 

 a good line of soundings across the ridge in 36° W, 

 with a least depth of 297 fm. (543 m.), and this was 

 shown in our previous chart. For a large part of the 

 year this region is covered by pack-ice, and it is 

 unfortunate that in subsequent years the ship was 

 not able to be there in the late summer when open 

 water may be expected. The ridge is thus still 

 inadequately explored, but one new line of soundings 

 was obtained in November 1932, when the ice was 

 farther south than usual for that month (see Mack- 

 intosh & Herdman, 1940, pi. Ixix), and this can be 

 seen in PI. XXIII as an irregular line running from 

 the South Orkney towards the South Sandwich 

 Islands. The line is irregular because the ship was 

 skirting the pack-ice throughout the passage. It would 

 at any time be difficult to lay a course between the 

 South Orkney and South Sandwich Islands which 

 would include soundings on unknown parts of the 

 ridge, but it happens that the course determined for 

 us by the pack-ice resulted in some very informative 

 soundings, especially between the meridians of 38^ 

 and 32° W. Here four well-marked areas of less than 

 1000 m. (547 fm.) in depth were found and in two 

 of these the minimum depth was less than 500 m. 

 (273 fm.). 



This line first ran south from the South Orkneys to the ice-edge in the latitude of 61° 57' S, and 

 then turned to the east to follow the ice-edge. The soundings obtained on the southerly run, together 

 with those at the beginning of the easterly course, show a remarkable extension of the South Orkney 

 shelf to the south and east.^ The first part of the eastward course must have lain south of any main 

 connecting ridge, for it was not until the ship turned almost north in 37^° W that the first bank was 

 located. Here six depths of less than 1000 m. (547 fm.) were determined and of these one was less than 



1 Soundings taken here by the 'Walter Rau' have already been mentioned in the footnote to p. 66 and they confirm this 

 extension of the South Orkney shelf. Stocks's map, however, is on a comparatively small scale and it is probable that the 

 soundings attributed to the 'Walter Rau' represent only a fraction of those taken. Nevertheless, of those plotted, there are 

 25 of less than 2000 m. (1094 fm.) and 20 of less than 1000 m. (547 fm.). They are in close agreement with our soundings and 

 although it is not now possible to include them in our bathymetric chart (PI. XXIIl) their inclusion would have caused only 

 local variations in the general trend of the contours shown for the South Orkney shelf. 



Fig. 14. The South Sandwich Islands. 



