SOUNDINGS TAKEN DURING THE DISCOVERY INVESTIGATIONS, 1932-1939 67 



with the further selection of our soundings which has been inserted on the relevant British Admiralty 

 Charts. His interpretation of the outline of the northern and central portions of the South Sandwich 

 Trench agrees therefore fairly closely with ours, although it lacks the confirmatory detail supplied by 

 our more complete data. At the southern end, where all the soundings available are, with one 

 exception, from the ' Discovery II ', those used by Stocks, which are presumably those selected by the 

 Admiralty from our lists and inserted in proportion to the scale of the relevant chart, are not quite 

 sufficient in themselves to provide an adequate basis for bathymetric purposes. As we have shown in 

 PI. XXIII we consider that it is more probable that the 5000 m. contour, on the eastern side of the 

 Trench, follows the line of the Trench to the south-west and that it does not join up with the small 

 deep area of more than 6000 m. which lies approximately between the meridians of 22° and 23° W in 

 latitude 61° S. In general the topography of the sea bed in this area appears to be extremely irregular 

 and it is more likely that this secondary deep area, together with the area of more than 5000 m. in depth 

 lying between 22° W and 25° W, in 62° S, are further evidence of the system of parallel folds which is 

 so prevalent in other sectors of the Scotia Arc. 



The Scotia Sea and South Sandwich Trench are also included in a bathymetric Map of Antarctica 

 (1939) produced by the Department of the Interior, of the Commonwealth of Australia. As in Stocks's 

 chart, this map is contoured in metres, and for the area in which we are concerned the contours in 

 general follow closely those of our previous bathymetric chart, but a considerable number of amend- 

 ments have been made to conform with our more recent work. This is most noticeable in the Burdwood 

 Bank-Shag Rocks section of the connecting link, though the lack of a 500 m. contour here tends to 

 give the impression that the Burdwood Bank is part of the continental shelf on which the Falkland 

 Islands lie, rather than an integral part of the Arc, as is shown clearly on our present chart. The 

 outline of the South Sandwich Trench agrees well with our latest interpretation of the soundings 

 here, and certain of our shallow soundings between the South Sandwich Islands and the South Orkneys 

 have been plotted. The wide shelf to the south and east of the latter group of islands is also well 

 defined. The complicated form of the link between Coronation Island (South Orkneys) and Clarence 

 Island is extremely well shown for the small scale used, as is also the trough which extends through 

 the Bransfield Strait to a position south of Clarence Island. 



The third recent bathymetric chart is U.S. Chart No. 2562 produced by the United States 

 Hydrographic Office in 1943. This map, which comprises a wide area around the Antarctic Continent, 

 is contoured in fathoms ; it is not, therefore, so easily compared either with our own chart or with 

 those of Stocks and the Commonwealth of Australia. There are, however, certain discrepancies in the 

 Scotia Sea area (some of which are referred to in a brief review by Hinks & Mackintosh, 1943), and 

 these should be mentioned here, since it would appear that some of the data available have been 

 overlooked. Perhaps the most important discrepancy is in the representation of the South Sandwich 

 Trench, where the deep water at the north-western extremity is shown as lying mainly south of latitude 

 55° S with a pronounced south-westerly trend, and where also the width at the southern end is given 

 as some 60 miles between the 3500 fm. (6401 m.) contours. Between the 3000 fm. (5487 m.) contours 

 in the same latitude the width of the Trench is shown as approximately 80 miles. Both these widths 

 are far in excess of either our own or the Australian interpretation of the data then available. In 

 the neighbourhood of the South Orkneys the Bart Bank (in approximately 6i" S, 41" 20' W) is shown 

 as part of the ridge connecting these islands with the South Sandwich Group, but, if reference is 

 made to British Admiralty Chart No. 3176, the soundings there shown give little indication that this 

 bank is connected with the South Orkney shelf. In view of the previous evidence of multiple folding 

 in the various sectors of the Arc it is, in our opinion, more probable that this is an isolated bank 

 or part of a bank, which lies in an east and west direction and which is parallel to the main 



