SOUNDINGS TAKEN DURING THE DISCOVERY INVESTIGATIONS, 1932-1939 81 



end of the South Shetlands and closely resembles a fjord. A trough with depths of more than 250 m. 

 (137 fm.) extends almost to the head of the bay and although the 500 m. (273 fm.) contour along the 

 south coast of the island lies several miles south of the entrance, soundings of more than 500 m. 

 (273 fm.) have been obtained over a distance of 2 miles on a northerly course, just inside the entrance 

 to the bay. The slope down from the coastal shelf at the western side of the entrance is considerable. 

 On a course round Telefon Rocks into the centre of the trough the soundings increased from 35 to 

 220 fm. (64 to 402 m.) in 0-45 mile; this is equivalent to a slope of 25" and, since it is probable that 

 our course was not at 90° to the line of the contours, the actual slope may well be a few degrees 

 greater. 



Farther to the east the 250 m. contour along the southern coast of King George Island swings north 

 towards King George Bay and there appears to be a comparatively narrow trough of this depth 

 extending about a mile into the bay. The slopes, however, are quite gentle and the greater part of the 

 bay appears to be reasonably shallow. Continuing round the coast of King George Island to Cape 

 Melville we find that the coastal shelf, with the exception of a few shallow indentations, remains fairly 

 wide. To the east of King George Island we had assumed (Herdman, 1932) that a ridge with depths 

 of less than 250 m. (137 fm.) existed between this island and Elephant Island (see p. 76). Our more 

 recent work makes this assumption doubtful, and it is now considered more likely that the 250 m. 

 contour swings north about 15 miles east of Cape Melville and then continues round the northern 

 side of the island. 



On the northern side of the South Shetlands there is a wide submarine shelf of less than 250 m. 

 (137 fm.) in depth. It is generally quite flat, although the continuous sounding records occasionally 

 show a sharp submarine peak suddenly rising some 150 to 200 ft. from it. One such peak, near Table 

 Island, rose 198 ft. (Record XXX/34) from a level bottom of 57 fm. (104 m.) in less than a minute 

 and normal soundings of more than 50 fm. (91 m.) were again being obtained within i^ min. As the 

 speed of the ship was 3^ knots this was equivalent to an upward slope of nearly 42'. These peaks, 

 perhaps, are only to be expected, for, in sharp contrast to the southern side of the group, the northern 

 coasts of the South Shetland Islands are infested with small islets and sunken rocks. As we have 

 already stated, navigation is extremely difficult, even in fine weather, and for our running survey it 

 was normally necessary to keep well offshore. The term 'foul', used in many places on the British 

 Admiralty Chart of these regions (No. 3205), is an accurate description of these coasts. 



The survey of 1936-7 finished with an examination of Gibbs, Aspland, Eadie and O'Brien Islands, 

 though these are not strictly part of the South Shetland Group. These islands lie in a group about 

 20 miles south-by-west of Elephant Island, and our survey in February 1937 showed that Aspland, 

 Eadie and O'Brien Islands lie together, in a north and south line, at the western side of the group. 

 Gibbs Island, which is the largest in the group, lies in an east and west direction. Narrow Island, 

 previously shown as a separate island near Gibbs Island, does not appear to exist. It is probable that 

 it has been confused with a low conical hill connected to Gibbs Island by a sand spit some 2 miles in 

 length which runs out in a south-easterly direction. Continuous soundings were taken around Gibbs 

 Island, and close to Aspland Island, for a total of 18 hr. in two days, and these represent a survey of 

 52 miles of the sea bed (see Text-fig. 5a, p. 49). Considerable alterations were made to the previous 

 conception of the outlines of the various islands comprising the group, and the soundings showed that 

 all the islands were steep-to. The slopes, however, were moderate in comparison with those generally 

 recorded in the South Shetlands. 



