SEA-FLOOR DEPOSITS. PART I 333 



Station WS 383. 15. ii. 29. Lat. 62 20' 40" S. Long. 58 13' W. 2085 m. (Plate XX.) 

 Diatomaceous MUD. This dark, greenish brown mud is finer in grain than the last, and contains 

 more diatom frustules. Among the latter Coscinodisciis, Thalassiosira, Cocconeis, Fragilaria, Corethron 

 and Rhizosolenia are noted. Some retain their protoplasmic content which is similar in appearance to 

 the fine-grained flocculent material. The mineral grains (chiefly subangular fragments of quartz) 

 range downwards from a diameter of about o-i mm. 



Station WS 384. 15. ii. 29. Lat. 62 25' 40" S. Long. 58 06' 10" W. 1957 m. (Plate XX.) 

 Diatomaceous mud. This sample shows close resemblance in general characters to that from 

 St. WS 383. The assemblage of diatoms contains the same genera, but the great abundance of large 

 and well-developed frustules of Corethron and Rhizosolenia is worthy of special mention. 



Station WS 385. 16. ii. 29. Lat. 62 32' S. Long. 57 55' W. 1838 m. (Plate XX.) 

 Diatomaceous mud. This sample is typical of its kind, and differs in no essential particular from 

 those last described. It contains the same assemblage of diatoms, namely Coschwdiscus, Thalassiosira, 

 Cocconeis, Fragilaria, Corethron and Rhizosolenia in quantity. The protoplasmic contents of some 

 diatoms are seen within the valves, and appear to contribute to the flocculent aggregates. The 

 preserving liquid is tinted green. The average size of the sand grains is perhaps smaller than in the 

 preceding samples. 



Station WS 386. 16. ii. 29. Lat. 62 41' S. Long. 57 44' W. 1392 m. (Plate XX.) 

 Diatomaceous mud. The largest sand grains in this sample attain a diameter of 0-3 mm. and grade 

 downwards in size. The proportion of large grains, however, is not sufficient materially to affect the 

 general constitution of the deposit which is closely similar to those from preceding stations. The 

 diatoms include species of Coscinodisciis, Thalassiosira, Cocconeis, Fragilaria, Rhizosolenia and 

 Corethron. 



Station WS 387. 16. ii. 29. Lat. 62 49' S. Long. 57° 40' W. 640 m. (Plate XX.) 

 Diatomaceous mud. This sample is much coarser in grain than the preceding, many of the 

 angular mineral grains reaching a diameter of 0-5 mm., though the average is much less. Occasional 

 grains of a glauconitic mineral are noted. The mineral content is perhaps larger in proportion than in 

 the former samples, but the diatomaceous material is still important. The genera Coscinodisciis, 

 Thalassiosira, Cocconeis, Fragilaria, Corethron and Rhizosolenia are present in quantity, along with 

 sponge spicules. The preserving liquid is coloured green and many of the diatoms retain their 

 organic content. 



Station WS 388. 16. ii. 29. Lat. 62 55' 30" S. Long. 57 40' W. 446 m. (Plate XX.) 

 Diatomaceous mud(?). This sample consists only of a small quantity of mud and a few small 

 pebbles. As green mud is also recorded in the Station List, the sample seems to be incomplete, and it 

 can only be said that the small quantity of fine material available resembles a diatomaceous mud. 



Station WS 389. 16. ii. 29. Lat. 63 17' S. Long. 58 51' 05" W. 130 m. (Plate XX.) 

 Sand. Many of the mineral grains in this sample reach a diameter of 0-5 mm. and the deposit is 

 not coherent. As a rule the grains of volcanic glass are somewhat angular in shape while those of 

 quartz are somewhat rounded. Diatom frustules are present in the fine-grained flocculent material, 

 but mainly in a broken condition; some undamaged valves of Coscinodisciis, Cocconeis and Biddulphia 

 are noted. 



Station WS 391. 17. ii. 29. Lat. 63 02' S. Long. 59 12' W. 877 m. (Plate XX.) 

 Diatomaceous mud. The bulk of the deposit consists of diatom frustules and small mineral grains, 

 in a "matrix" of flocculent material. The chief genera of diatoms are: Coscinodisciis, Thalassiosira, 

 Triceratium , Cocconeis, Fragilaria, Thalassiothrix, Corethron and Rhizosolenia. While the great 

 majority of the mineral grains are less than o-i mm. across, some reach a diameter of about 0-5 mm. 

 The largest are angular fragments of brown volcanic glass; quartz grains are smaller and more 

 rounded. 



