304 DISCOVERY REPORTS 



washed out". The presence of small pebbles, however, at depths of 3369 and 1602 m. 

 is unexpected, especially as the former locality is within the belt of Globigerina ooze. 

 In view of the uncertainty as to the constitution of these samples, the deposits are not 

 shown on the accompanying map. 



St. WS 406, on the northern side of Drake Strait, yields a foraminiferal sand from a 

 depth of 1234 m. The proportion of sand grains forbids reference to this deposit as an 

 ooze, though Pirie postulates a belt of Globigerina ooze through Drake Strait. It may be 

 recalled that the same difficulty occurs with regard to a sample from St. WS 403 farther 

 south, which is tentatively classified as diatomaceous mud (p. 303). 



A clean coarse sand from St. 381, just west of Elephant Island in the South Shetlands, 

 at a depth of 425 m., is noteworthy for the presence of garnet among the detrital 

 minerals. 



Two samples of sand from the South Sandwich Islands (Sts. 363 and 366) are 

 remarkable for the abundant fragments of vesicular volcanic glass, the angularity and 

 freshness of which proclaim their local origin. These stations, with depths of 329 and 

 340 m., lie on the eastern part of an arcuate submarine ridge which connects South 

 Georgia with the South Orkney Islands, and includes the South Sandwich group. The 

 latter islands are recorded 1 as volcanic centres, and doubtless the sands are formed by 

 the denudation of the eruptive material. 



The two remaining sands are from Sts. 160 and WS 314, in the neighbourhood of the 

 Shag Rocks, west of South Georgia, at depths of 177 and 137 m. respectively. The most 

 interesting feature is the presence at St. WS 314 of colourless flakes some of which 

 show hexagonal outlines; the radial texture of many suggests that they are zeolitic 

 aggregates formed by the decomposition of volcanic rock. 



THE WEST AND SOUTH COASTS OF AFRICA (Plate XVII inset) 



Seventeen stations, namely Sts. K, L, M, 89, 93, 94, 95, 96, 97, 98, 101, 102, 263, 

 264, 265, 283 and 425, are grouped in this area. The most northerly station (283) off 

 Annobon in the Gulf of Guinea is outside the limits of Plate XVII. The sample is a fairly 

 coarse foraminiferal sand, containing very few mineral grains; the depth is recorded as 

 18-30 m. 



The remaining samples were collected off the south and south-west coasts of Africa. 

 The stations are shown on Plate XVII (inset), with the exception of the isolated St. 425, 

 south-east of Port Elizabeth, which is outside the eastern limit of the map. The samples 

 from the stations nearest land (Sts. 93, 94, 95, 96, 97, 263, 264, 265) contain the mineral 

 glauconite, though this constituent is not abundant in any of them. It generally occurs 

 in rounded grains, some of which are compound or lobate. In some samples (e.g. 

 St. 96) the glauconite is seen infilling the chambers of broken Globigerina shells. These 

 foraminiferal tests are so abundant at Sts. 95, 96 and 97 that the samples might almost 



1 Douglas, G. W., and Campbell Smith, W., 1930. Zavodovski Island, and notes on Rock Fragments 

 dredged in the Weddell Sea. Quest Report, p. 63. Kemp, S., and Nelson, A. L., 1931. The South 

 Sandwich Islands. Discovery Reports, III, p. 150. 



