,86 DISCOVERY REPORTS 



direction towards deeper water. The grade forms up to 7 per cent of the deposits off the 

 southern entrance of Falkland Sound. 



On the Burdwood Bank coarse gravel forms up to 19 per cent of the deposits on the 

 top of the bank, but the proportion drops to only 2 per cent as deeper water is ap- 

 proached to the north. 



(IV) MEDIUM GRAVEL (Plate VII) 

 (Particles over 2-5 mm. and under 5 mm. in diameter) 

 This grade is widely distributed over the region examined. It is absent only from (1) a 

 belt about 60 miles wide running south-east from the Gulf of San Jorge to lat. 40 S 

 and then turning eastwardly to deep water, (ii) from a coastal strip extending from Point 

 Deseado to Point Gallegos and (iii) from the deeper water below the edge of the con- 

 tinental shelf to the north-east of the Falkland Islands. 



The grade occurs over most of the region in small amounts, up to 5 per cent, but a 

 wide tongue in which the proportion is up to 24 per cent extends from the coast of 

 Tierra del Fuego in a north-easterly direction, narrowing to a point short of the Jason 

 Islands. A patch bearing up to 10 per cent of medium gravel lies south of the belt free 

 from the grade that runs south-westerly and westerly from the Gulf of San Jorge. 



Deposits off the southern end of Falkland Sound carry 9 per cent of medium gravel, 

 as do those of a patch to the north of West Falkland Island. 



The rough patch to the north-east of the Falkland Islands, on the edge of deep water, 

 bears 7 per cent of the grade, whilst the shallower part of the Burdwood Bank shows 

 16 per cent decreasing to 10 per cent on the slope towards deeper water to the north. 



Four isolated patches bearing from 5 to 10 per cent medium gravel occur on the 

 continental shelf south of the Gulf of San Jorge. 



The highest proportion of this grade in any of the deposits is only 24 per cent, and if 

 the contour separating the percentages up to 5 per cent from the percentages 6-10 per 

 cent is removed, the wide and even distribution in small proportion of medium gravel 

 over nearly the whole of the region is emphasized. 



(V) FINE GRAVEL (Plate VIII) 

 (Particles over 1-5 mm. and under 2-5 mm. in diameter) 



This grade occurs in small proportions over the whole region examined with the 

 exception of the Gulf of San Jorge, a coastal strip from Point Deseado to Point Gallegos, 

 and three isolated patches, one about the middle of the continental shelf east of Point 

 Deseado, another on the edge of deep water farther to the east, and the third in the 

 deep water lying between the Burdwood Bank and Tierra del Fuego. 



Fine gravel forms up to 9 per cent of the deposits in coastal belts to the north and 

 south of West Falkland Island, and in two large grounds lying between the Falkland 

 Islands and Patagonia and Tierra del Fuego. It also forms up to 7 per cent of the 

 rough patch to the north-east of the islands. On the Burdwood Bank it is present up to 

 4 per cent on the shallower parts and increases to 12 per cent towards the deeper water 

 to the north. Three small areas carrying up to 10 per cent of this giade lie on the 



