SOUTH GEORGIA AND THE SHAG ROCKS 221 



From 47° W to the Shag Rocks many more soundings are necessary before the 

 contours can be drawn in accurately, but from the soundings now available it will be 

 seen that there can be no doubt as to the existence of a ridge. 



Previous bathymetric charts of this area have shown the Rhine Bank in a position 

 approximately 55° 30' S, 53"^ 30' W with a depth of 121 m. In January' 1926 the 'Meteor' 

 searched unsuccessfully for the Bank,^ obtaining a sounding of 3640 m. very close to the 

 charted position, and in the course of the season 1931-2 the 'Discovery II' passed 

 between the Rhine Bank and the Burdwood Bank, obtaining soundings of 2500 3000 m. 

 within 25 miles of the former. In view of this recent evidence the Rhine Bank has been 

 omitted both from our sounding and bathymetric charts. 



SOUTH GEORGIA AND THE SHAG ROCKS 

 (Plates XLV, XLVI, Charts 3, 5) 



The chart of South Georgia and the Shag Rocks (No. 5) shows the majority of the 

 soundings obtained during the Discovery investigations since February 1925. They 

 number approximately 1600 and have mostly been taken by the echo method. Certain 

 inshore soundings taken in the bays and harbours during Lt.-Cmdr. Chaplin's survey^ 

 have been omitted, as the scale of the chart is too small to insert more than a very small 

 proportion. The bathymetric chart (Plate XLVI) is based mainly on the 1600 soundings, 

 although account has been taken of all other available soundings, especially those of the 

 'Quest' and 'Meteor'. These and other soundings not obtained during the Discovery 

 investigations are shown on the bathymetric charts by circles as opposed to the black 

 dots which represent our soundings. 



Nearly all these soundings round South Georgia and two of the lines between Willis 

 Island and the Shag Rocks were obtained during the various plankton surveys. During 

 these surveys lines of stations are worked out to a distance of 1 00- 1 20 miles from the land , 

 starting from various points round the island. By coming back diagonally from the outer 

 end of one line to the shore end of the next and by changing the starting-points and the 

 angles of the lines with the land, it has been possible to cover a considerable amount of 

 ground. It was also usual when proceeding to and from South Georgia to set a slightly 

 different course on each occasion, which accounts for the greater number of soundings 

 obtained on the northern side of the island. 



As a result of the survey work carried out between 1926 and 1930 by Lt.-Cmdr. 

 Chaplin, R.N., and the running surveys made by Lieut. Nelson, R.N.R., in 193 1, con- 

 siderable alterations have been made in the charted coast-line of the island, and as a result 

 of this work it has been necessary to omit as unreliable certain soundings which were fixed 

 by land bearings. With regard to the bathymetric chart, soundings from other sources 

 which are known to have been fixed from the land have been adjusted to the new outline 

 of the land as far as possible and doubtful ones have again been omitted. 



^ Whs. Ergebn.Deutsdi.Atlant.Exped. 'Meteor ', I, p. 17s ■ 



2 Lt -Cmdr Chaplin, R.N. Narrative of Hydrographic Survey Operations in South Georgia and the 

 South Shetland Islands,' 1926-3°. Discovery Reports, iii, pp. 297-344. Pls- XL-XLIV, Charts 1-4 (1932)- 



