SEA-FLOOR DEPOSITS. PART I 301 



the ooze from terrigenous deposits ; moreover the sample contains grains of glauconite. 

 Three stations, namely, WS 520, WS 521, and WS 522, which lie between the Falkland 

 Islands and South Georgia, between lat. 52 and 53 ° S, represent the most southerly 

 localities from which Globigerina ooze was collected by the Discovery Expeditions. 

 A noteworthy feature at St. WS 522 is the presence of a fair proportion of diatoms 

 among the smaller organisms ; but an extensive area occupied by diatom ooze occurs at 

 no great distance to the east. The deposit at St. WS 522 also contains the zeolite mineral 

 phillipsite along with coarse sand grains and occasional pebbles, the latter up to 1 cm. 

 in diameter. Another occurrence of pebbles at an even greater depth in the same area 

 (St. WS 317) is mentioned on p. 304 of this report. In general, Globigerina ooze is 

 confined to stations of considerable depth (2000-4600 m. in the present investigation) 

 situated far from land. The occurrence of pebbles in such deposits is therefore an 

 unusual feature; in this instance it seems to be connected with the unusually varied 

 character of the submarine topography. 1 



Radiolarian ooze. Hitherto, no radiolarian ooze has been recorded from the South 

 Atlantic Ocean, but the Discovery Expedition obtained samples of this deposit in the 

 western part of the region from Sts. 71, 74 and 77, at depths of 5460, 5446 and 5186 m. 

 respectively. In an examination of the deposits themselves, Radiolaria are not much in 

 evidence, being obscured by the finer material, but the organisms are very plentiful in 

 coarse washings from the sediments ; diatoms and sponge spicules occur in subordinate 

 quantity. Reference to Plate XVI I shows that radiolarian ooze must occupy a considerable 

 area in this part of the South Atlantic which was included by Murray and also by Pirie 

 in the belt of Globigerina ooze. It may be noted that St. 71 is near the middle of the 

 Argentine Basin. 2 Another sample of radiolarian ooze was obtained at St. 11 65 (long. 

 9 25-5' E, lat. 40 547' S) at a depth of 4642 m. 



Diatom ooze. Five samples of diatom ooze were obtained by R.R.S. 'Discovery' 

 along a north-east-south-west line, north-east of South Georgia. The samples from 

 Sts. 10 and 11 are recorded in the Station List as "radiolarian ooze", but Radiolaria 

 are found to be subordinate to diatoms in these deposits. Four stations made by the 

 'William Scoresby' south-west and west of South Georgia also yield typical diatom 

 ooze. Hence a wide stretch of ocean in this region is marked by the abundance of 

 diatoms and the absence of Foraminifera. The occurrence of diatomaceous deposits here 

 does not conform to Murray's map which includes the area in the belt of Globigerina 

 ooze, as does the later map of Pirie. 3 The most westerly of these stations, namely, 

 WS 377 and WS 429, are in approximately 45 W long. This appears to be near the 

 western limit of the diatom ooze, for St. WS 522, in 47 W long, and about the same 

 latitude as St. WS 429, yields Globigerina ooze. These stations lie along the line of a 

 submarine ridge which can be traced almost continuously between the Burdwood Bank, 



1 See Herdman, H. F. P., 1932. Report on Soundings, etc. Discovery Reports, VI, p. 219 and plate xlv. 



2 See Wust, G., 1933. Wiss. Ergebn. Deutschen Atlant. Exped. 'Meteor', VI, i, plate viii. 



3 Pirie, J. H. H., 1913. Deep-Sea Deposits of the Scottish National Antarctic Expedition. Trans. Roy. 

 Soc. Edin., xlix, pp. 645-86. 



