SEA-FLOOR DEPOSITS. PART I 34» 



Station WS 514. ii.ii. 30. Lat. 66° 40!' S. Long. 71° oi'W. 531m. (Plate XXI.) 

 Diatomaceous mud. The sample contains flocculent material of the same type as the foregoing 

 sample but less abundantly. It encloses frustules of Coscinodiscus, Thalassiosira, Biddulphia and 

 Fragilaria. The mineral grains attain a larger size, angular grains of quartz and green hornblende 

 reaching o-2 mm., and dark opaque grains 0-25 mm. in diameter. 



Station WS 515. ii.ii. 30. Lat. 66° 3^' S. Long. 71° aoi'W. 512 m. (Plate XXI.) 

 Diatomaceous mud. The deposit is of the same type and contains the same diatoms as the pre- 

 ceding samples. Mineral grains are perhaps more abundant ; angular grains of quartz reach 02 mm. 

 and green hornblende o-i mm. in diameter. 



Station WS 516. 12. ii. 30. Lat. 66° 25!-' S. Long. 71° 38J' W. 261 1 m. (Plate XXI.) 

 Sand. The sample has separated into layers during storage, brown mud above, and dark-coloured 

 sand below. 



The former consists of tiny mineral grains usually less than o-oi mm. in diameter, together with 

 plentiful tests of Radiolaria, occasional whole frustules of diatoms, and a fair proportion of frag- 

 mentary tests. The coarser fraction contains mineral grains up to 1 mm. in diameter, chiefly angular 

 grains of quartz and opaque rock fragments. These give character to the deposit which must be 

 classed as a sand. 



Station WS 517. 12. ii. 30. Lat. 66° 17J' S. Long. 71° 57' W. 2770 m. (Plate XXI.) 

 Diatomaceous mud. This brown mud consists largely of detrital mineral grains, which are mostly 

 below 0-05 mm. in diameter though occasional grains are 0-25 mm. across. Angular fragments of 

 quartz (up to 0-25 mm.) and prismatic grains of green hornblende (o-i mm. long) are the most 

 abundant minerals. The finer fraction contains a large proportion of tiny angular grains, mingled 

 with flocculent material which consists partly of diatom debris. Recognizable organic remains are not 

 abundant, but they include the diatoms Fragilaria, Cocconeis and Coscinodiscus, along with fragments 

 of radiolarian tests. The diatomaceous material is sufficiently important to be taken into account 

 with the mineral content in classifying this deposit. 



Station 518. 27. ii. 30. Lat. 51° 55V S. Long. 55° 35' W. 1258 m. (Plate XVII.) 

 Glauconitic mud. This is a greyish deposit with dark-coloured sand grains. The coarser fraction 

 consists of foraminiferal shells, fragments of quartz and grains of glauconite. The latter reach a 

 diameter of about 0-5 mm., and they retain the shape of foraminiferal tests which they once infilled ; 

 Globigerina and textularian forms are represented, and portions of the shell still adhere to some of the 

 grains. The quartz grains are usually smaller. Unbroken tests of Globigerina, Orbulina and rotalines 

 are plentiful. The finer fraction consists of comminuted foraminiferal shells together with tiny 

 quartz grains, broken sponge spicules and occasional Radiolaria, the whole often forming flocculent 

 aggregates. 



Station WS 520. 27-28. ii. 30. Lat. 52° 25' S. Long. 51° 20' W. 3128 m. (Plate XVII.) 

 Globigerina ooze. A small quantity of light-coloured deposit with dark grains. The bulk of the 

 sample consists of well-developed tests of Orbulina and Globigerina, up to o-i mm. in diameter, many 

 of which are undamaged. The dark grains, with the same average diameter, are glauconitic moulds of 

 Globigerina from which the shell has dissolved ; the septa of the test remain, however, so that the 

 mould can be identified. There are also angular grains of quartz which are usually smaller than the 

 Foraminifera. The small proportion of flocculent matter consists of coccoliths, rhabdoliths, and tiny 

 fragments of disintegrated Globigerina shells, the aggregates often enclosing small mineral grains. 



Station WS 521. 28. ii. 30. Lat. 52° 41' S. Long. 49° 14' W. 3780 m. (Plate XVII.) 

 Globigerina ooze. This is similar in general characters to the preceding sample, but the propor- 

 tion of mineral grains is larger. Many of the grains reach a diameter of o-i mm., while a few are 

 0-4 mm. across. The proportion of fine flocculent material is perhaps greater than in the former 

 sample and a few diatoms are present. 



