SEA-FLOOR DEPOSITS. PART I 305 



be described as Globigerina ooze; but they contain a fair proportion of mineral grains, 

 and the presence of glauconite gives a distinct character to the deposit. Glauconitic 

 mud is accumulating at depths of 165 to nearly 1000 m., to a distance of some 60 miles 

 from the coast, while the Agulhas Bank, long famed for glauconitic deposits, lies at no 

 great distance to the south-east. Farther west, at Sts. 89, 98, 101 and 102, typical 

 Globigerina ooze with only occasional mineral grains occurs at depths of 3926, 3640, 

 3734 and 1800 m. respectively. 



THE FALKLAND ISLANDS (Plate XVIII) 



The twenty-eight samples from this region are of very uniform character. Most of 

 them are sands composed essentially of terrigenous material. The depth is slight, 

 varying in different parts of the area between 23 and 251 m.; and the region is uni- 

 versally accepted as forming part of the South American continental shelf. 



Recently, these sands have been classified by L. H. Matthews 1 on the basis of 

 mechanical analysis, with the object of providing data concerning the habitats of the 

 organisms which live on them. Geologically, the chief interest of these deposits lies in 

 their mineral content, but as this will be fully discussed in a future report, only a brief 

 reference to minerals of common occurrence need be given here. Like the majority of 

 sands, these contain a preponderance of quartz grains, and this feature may be corre- 

 lated with the wide distribution of sandstones and quartzitic rocks in West Falkland 

 Island and the north part of East Falkland Island.' 2 The outstanding point of interest is 

 the abundance, in most of the samples, of well-formed (but worn) crystals of hypers- 

 thene, a mineral which is characteristic of the andesitic volcanic rocks of South America. 

 The sample from St. 48 yields rounded grains of red garnet and brown tourmaline in 

 addition to hypersthene. Foraminifera occur plentifully in some of the samples, and 

 diatoms are also present, either alone or associated with the Foraminifera. 



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

 is the Burdwood Bank, which is separated from the Falklands by comparatively deep 

 water. Two samples (Sts. WS 86 and WS 87) are available from the Burdwood Bank at 

 depths of 151 and 96 m. respectively. They consist of sandy deposits with a varied 

 assortment of shelly material including an abundance of Foraminifera. A sample from 

 the eastern portion of this bank, obtained by the Scotia Expedition (1903), has been 

 described by Pirie, 3 and the station was included by him in the belt of Globigerina ooze. 

 This, however, is hardly justified by his description of the deposit, as the Foraminifera 

 are said to be of shallow-water Antarctic types. The abundance of terrigenous material 

 in the deposits, considered in conjunction with the soundings, 4 shows that the Burdwood 



1 Matthews, L. H., 1934. The Marine Deposits of the Patagonian Continental Shelf. Discovery Reports, 

 ix, pp. 175-206. 



2 Baker, H. A., 1923. Final Report on Geological Investigations in the Falkland Islands (1920-1922), 

 Fol. London. 



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

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



4 Herdman, H. F. P., 1932. Report on Soundings, etc. Discovery Reports, VI, pp. 205-36. 



