62 DISCOVERY REPORTS 



The existence of a continuous ridge between the South Sandwich and South Orkney Islands has 

 been queried by Wiist (1933, pp. 44-5)) on account of the percolation of Antarctic- Atlantic water 

 into the ' South Antilles Sea ', at a point half-way between the South Sandwich group and the South 

 Orkneys. His facts are deduced from the potential bottom temperatures and in his illustration 

 (pi. ii) he shows a break of approximately go miles in the ridge, centred about 34° W, where a depth 

 of more than 2000 m. (1094 fm.) is to be expected. From our line of soundings along this part of the 

 ridge in 1932 it would appear that if such a break does exist in this position then its maximum width 

 must be considerably less than that deduced by Wiist. Our observations show that in the neighbourhood 

 of the longitude in question there can only be a maximum distance of 20 miles over which depths of 

 more than 2000 m. (1094 fm.) can be expected; in fact, the horizontal distance between the 1000 m. 

 (547 fm.) contours is only some 40 miles at this point. It should also be pointed out that, in view of the 

 extremely irregular form of the Arc in general and especially of the known complicated area west of 

 40° W longitude, it cannot be said that this one line of soundings gives a complete picture of the ridge 

 at the point in question. It is, in fact, very probable that a system of parallel ridges will be found to 

 exist here, similar to those found between Clarence Island and the South Orkneys. Some further 

 observations on this subject have been made by Deacon (1937, p. m), who shows that from the 

 hydrological point of view the existence of low-bottom temperatures in the Scotia Sea may not 

 necessarily be evidence of an inflow of cold bottom water from the Weddell Sea, but may well be due 

 to the formation of cold bottom water in the deeper regions of the Scotia Sea which lie north and west 

 of the South Orkneys. 



Considerably more detail in the delineation of the Scotia Arc has been made possible as the result 

 of the many further soundings taken by us in this area since 1932. The South Sandwich Trench,^ 

 which is perhaps the outstanding feature of the Arc, was crossed a further seven times between 

 December 1932 and March 1937, and four of these lines of soundings were far to the south of any 

 crossings previously made. We had always suspected that the Trench might extend farther to the 

 south and west than the earlier soundings had shown, and it now seems certain that its south-western 

 limit is not far from a position in 61° S, 26° W, with its line of curvature lying almost parallel to the 

 line of the South Sandwich Islands. At the northern end soundings taken in December 1932, and 

 August 1934, show that the deepest portion of the Trench extends about 60 miles farther west than 

 hitherto determined, and that the 5000 m. contour now lies some 30 miles nearer to South Georgia, 

 extending almost to the 4000 m. contour. The length of the Trench can now be stated with fair 

 accuracy; at depths of more than 5000 m. (2734 fm.) it extends for approximately 650 miles and at 

 depths greater than 7000 m. (3829 fm.) the length is approximately 500 miles. The maximum depth 

 of 8264 m. (4519 fm.) obtained by the ' Meteor' in 1926 was not exceeded but, in December 1932, in 

 54° 57' S, 29° 26' W we obtained a sounding of 8200 m. (4484 fm.), which was 98 m. (179 fm.) in excess 

 of our previous record of 8102 m. (4430 fm.) in 56° 33' S, 24° 33' W. In all the seven crossings made 

 since 1932 we obtained fifty-five soundings of more than 5000 m. (2734 fm.) and of these thirty-one 

 were of more than 6000 m. (3282 fm.), thirteen of more than 7000 m. (3829 fm.) and one of more than 

 8000 m. (4376 fm.). From the evidence now available it appears reasonable to assume that the Trench 

 has a depth considerably in excess of 7000 m. (3829 fm.) for the greater part of its length, though it 



1 It is considered that the name 'South Sandwich Trench', in accordance with Littlehales's terminology, is preferable to 

 'South Sandwich Deep'. We are not, however, in agreement with the suggestion made by Wiist (1940, p. 20) and others that 

 the deepest known parts of the Trench should be called Meteor Deep and Discovery Deep respectively. Since those soundings 

 of more than 8000 m. were obtained, the ' Discovery II ' has obtained a sounding of 8200 m. some 90 miles west of the 'Meteor's' 

 greatest depth and nearly 200 miles distant from the greatest depth previously determined by the 'Discovery II'. A more 

 complete survey of the Trench may well disclose even greater depths, especially if the recorder can be used, and it seems 

 premature to give names to the deepest parts which so far happen to have been found. 



