SOUTH SANDWICH ISLANDS TO SOUTH ORKNEY ISLANDS 225 



55° 28' S, 31° 47' W. On the northern side the 4000 m. contour clearly shows that the 

 influence of the South Sandwich Deep can be traced to a position about 40 miles north- 

 north-east of the Gierke Rocks. Fig. 2 a shows a section taken across the ridge into this 

 part of the Deep and Fig. 4 a shows a section farther to the east, crossing the Deep at 

 an oblique angle. 



From the trend of the looo and 2000 m. contours to the south-east of the Gierke Rocks 

 and to the north-west of Zavodovski Island it is probable that soundings taken along a 

 line about 10 or 15 miles south of the existing intensive lines of soundings will show that 

 the crest of the connecting ridge lies to the south of where it is now placed on the 

 sections and bathymetric chart. The data now available show the possibility of two 

 gaps in about 29° 30' W and 31° W. 



The 'Meteor' ran a line of echo soundings across this ridge during February 1926, 

 starting from about 56° 30' S, 31° 00' W and proceeding in a north-easterly direction. 

 From these soundings evidence was obtained that there was a double ridge at this point, 

 the separate peaks having approximately the same depth of water of 2400 m.' This depth 

 is slightly less than the average found by the Discovery Investigations, but without more 

 detailed information as to the position of these soundings they cannot be compared with 

 our interpretation of the bottom relief. It seems probable, however, that they lie to the 

 south of our lines. Pratje, in his bathymetric map, does not show any indication of this 

 shoaling between South Georgia and the South Sandwich Islands, but his contours, like 

 ours, are drawn at 1000 m. intervals. With the data at present available it appears that 

 no intermediate contour will show the existence of a continuous connexion, and that 

 in this section of the arc the depth of water on the ridge may be only 400-700 m. less 

 than the average of that at the eastern end of the Scotia Sea. 



SOUTH SANDWICH ISLANDS TO SOUTH ORKNEY ISLANDS 



(Plate XLV, Gharts 3, 4) 



The ridge connecting the various islands of the South Sandwich Group has already 

 been discussed during the description of the South Sandwich Deep, so that the next 

 section of the arc to be considered is from Southern Thule, in the above group, to the 

 South Orkney Islands. Here we have been unfortunate each season with regard to ice 

 conditions, and it was not till early in 1932 that the 'Discovery 11' was able to obtain 

 a line of echo soundings which crossed the ridge from south to north in about 36° W. 

 This line is within 40 miles of the line of soundings taken by the ' Deutschland ' in 1912,- 

 and examination of the contours will show that these observations have been confirmed. 

 The minimum sounding found by the 'Discovery 11' was 543m. in approximately 

 60" 20' S, 36° 03' W, and the section based on this line (Fig. 4 h) shows that the main 

 ridge is roughly 60 miles wide at this point with an average depth of water of about 

 1000 m. To the south a narrow trench over 4000 m. deep is found, followed by a 



1 Whs. Ergebn. Deutsch. Atlant. Exped. 'Meteor', I, p. 183. See also Stocks, loc. cit., supra. 



2 Brennecke, Arch. Deulsch. Seewaric, xxxix, Nr. i, tafel 2 (1921). 



