SEA-FLOOR DEPOSITS. PART I 335 



Station WS 400. 21. ii. 29. Lat. 62 07' S. Long. 62 33' W. 4517 m. (Plate XX.) 

 Diatomaceous mud. This brownish grey mud contains a considerable proportion of inorganic 

 material, unworn and angular mineral grains varying from o-i mm. in diameter to exceedingly small 

 dimensions. Besides quartz, grains of green hornblende, glaucophane and hypersthene are noted, 

 some of the latter showing crystal faces. There is much flocculent material which consists largely 

 of broken frustules of diatoms in all stages of disintegration. Whole frustules of Coscinodiscus, 

 Thalassiosira, Cocconeis and Fragilaria are of common occurrence. 



Station WS 403. 22-23. ii. 29. Lat. 59° 41' S. Long. 64 35' W. 3721m. (Plate XVII.) 

 Diatomaceous mud. The coarser fraction contains mineral grains up to o-i mm., mostly angular 

 in condition ; quartz, green hornblende and occasional grains of glaucophane are among the minerals 

 present. There is also some quantity of large tests of Globigerina and rotaline Foraminifera, together 

 with radiolarian tests. The finer fraction consists of flocculent material which includes whole and 

 broken frustules of diatoms, Coscinodiscus, Fragilaria, Cocconeis, Thalassiothrix being prominent 

 genera. 



This sample is not easy to classify. The coarse washing might almost be a Globigerina ooze, but 

 the proportion of mineral grains is too large. The finer material, which forms the greater proportion 

 of the deposit, has the typical constitution of diatomaceous mud. The deposit is therefore classified 

 as such, despite the unusual abundance of Foraminifera. 



Station WS 406. 24. ii. 29. Lat. 56 50' 30" S. Long. 67 03' W. 1234 m. (Plate XVII.) 

 Foraminiferal sand. The sample is a small quantity of sand which consists of quartz grains and 

 tests of Foraminifera. Among the latter Globigerina together with rotalines and textularians are 

 plentiful. 



Station WS 428. 29. vi. 29. Lat. 53 07' S. Long. 42 30' W. 1966 m. (Plate XVII.) 

 Diatomaceous mud. There is a considerable proportion of diatomaceous debris containing entire 

 frustules of Coscinodiscus, Cocconeis, Fragilaria and Thalassiothrix, together with sponge spicules and 

 occasional radiolarian tests. The finer particles form flocculent aggregates. The grains of the 

 mineral constituents vary in diameter from 0-25 mm. down to exceedingly small dimensions, and are 

 generally angular or subangular in shape. Most of the colourless fragments are of quartz, and some 

 of the opaque grains appear to be glauconite. 



Station WS 429. 30. iv. 29. Lat. 53 02' 30" S. Long. 45 28' W. 2549 m. (Plate XVII.) 

 Diatom ooze. This is a typical diatom ooze, formed almost entirely of frustules among which 

 species of Coscinodiscus, Thalassiosira, Cocconeis, Achnanthes, Rhizosolenia and Thalassiothrix are 

 noted. Fragments of radiolarian tests are also present. Mineral grains occur in small quantity; they 

 are mostly very small but occasionally grains of quartz and prisms of hornblende reach a length of 

 o-i mm. 



Station WS 433. 5-6. v. 29. Lat. 5i°44'S. Long. 56 23' W. 1035 m. (Plate XVII.) 

 Glauconitic mud. The sediment has formed layers in the storage bottle, dark sand below, light 

 brown mud above, and the liquid is coloured green. The coarser fraction consists of mineral grains 

 up to 0-25 mm. across. Many of these are rounded grains of glauconite, some of them infilling broken 

 foraminiferal tests; there are, however, many shells which do not contain glauconite. Grains of 

 quartz and hornblende are also noted. Foraminifera are represented by Globigerina and rotalines. 

 The finer fraction consists of small mineral grains, broken sponge spicules and flocculent matter. 



Station WS 468. 9-10. xi. 29. Lat. 55 52' S. Long. 56 53' W. 4344 m. (Plate XVII.) 

 Diatomaceous mud. This deposit contains a large proportion of mineral grains, some of which 

 reach a diameter of 0-2 mm. Quartz and green hornblende are conspicuous in angular grains, but 

 some fragments are well rounded. Occasional grains of garnet are noted. The finer material consists of 

 organic debris, sponge spicules and diatom frustules; most of the latter are fragmentary, but some 

 whole frustules of Coscinodiscus occur. Broken tests of Globigerina are present. 



