THE MARINE DEPOSITS OF THE 

 PATAGONIAN CONTINENTAL SHELF 



By L. Harrison Matthews, m.a. 

 (Plates II-XIV; text-figs. 1-3) 



INTRODUCTION 



This report is a description of the nature of the sea-bottom of the continental shelf 

 lying off the coasts of Patagonia and Tierra del Fuego south of lat. 43 S. This 

 region includes the Falkland Islands, and the Burdwood Bank which lies south of them. 

 It has been the subject of fishery surveys made by the R.R.S. 'William Scoresby', 

 when the region was explored by means of the large otter trawl, in addition to the usual 

 oceanographic gear, to ascertain whether it could sustain a commercial trawl fishery. 

 At many of the stations bottom samples were obtained with the conical dredge, and 

 these form the subject of this report. From the biological standpoint the type and 

 texture of the bottom deposits are of great importance when considered in relation to 

 the animals and plants found living on or near the bottom, or burrowing into it. For 

 this reason the deposits are here classified and charted into grounds showing the type 

 and size of the particles that form them, providing data of the habitats of the organisms 

 living on or near the bottom in the region examined. 



TOPOGRAPHY OF THE SEA-BOTTOM OF THE REGION 



The region from which bottom samples have been examined comprises the Pata- 

 gonian continental shelf south of lat. 43 S, and part of the Burdwood Bank. The 

 Patagonian continental shelf includes the Falkland Islands. Plate III shows the bathy- 

 metric configuration of the region. It is constructed from the soundings taken by the 

 R.R.S. 'William Scoresby', with additions from the Admiralty charts of the region. 



The limit of the continental shelf may be taken as the 200 m. contour. This contour 

 roughly follows the sixtieth meridian from lat. 43 ° to 46 S, then bends westward to the 

 neighbourhood of long. 61 ° W and follows this meridian to 49 S. Here it turns south- 

 east to lat. 51 S and then skirts the outline of the Falkland Islands, following the east, 

 south and west coasts to lat. 51 S in the neighbourhood of long. 62 W. At this point 

 it turns south-west and runs towards the mouth of the Strait of Magellan as far as 

 64 30' W, where it again turns southerly and runs down to the eastward end of Staten 

 Island. 



South of the Falkland Islands, between lat. 54 and 55 S and long. 56 and 62 W, 

 lies the Burdwood Bank, which shoals to less than 50 m. The bank is separated from the 

 Falkland Islands and the Patagonian continental shelf by deep-water channels which run 



