SEA-FLOOR DEPOSITS. PART I 343 



appearance and contains cells of green algae and diatoms, among which frustules of Coscinodiscus, 

 Rhizosolenia and Chaetoceros are noted. 



Station WS 599. 19. v. 31. Lat. 35° 41' 30" S. Long. 73 43' W. 3265 m. (Plate XXII.) 

 Diatomaceous mud. This is essentially similar in general constitution to the preceding sample. 



Some fragments of green hornblende are noted among the more abundant quartz grains. The 



diatoms include frustules of Coscinodiscus and Chaetoceros. 



Station WS 602. 28. v. 31. Lat. 32 04' 45" S. Long. 71 34' W. 75 m. (Plate XXII.) 

 Shelly sand. This sample consists largely of calcareous material which includes the brachiopod 

 Magellania flavescens (one entire shell), echinid spines, sponge spicules, fragments of gastropod 

 shells, Polyzoa, pteropods and Foraminifera. Mineral grains, chiefly angular fragments of quartz, reach 

 a diameter of 0-25 mm. Crystals of phillipsite (o-i mm.) are plentiful among the finer material. 



Station WS 604. 28. v. 31. Lat. 32 05' S. Long. 71 45' 30" W. 687 m. (Plate XXII.) 

 Terrigenous mud. A dark green mud, formed mainly of angular mineral grains of which a large 

 proportion are about o-i mm. in diameter. The minerals include quartz, white mica, green horn- 

 blende (some fibrous), staurolite (?) and volcanic glass. There is a small proportion of flocculent 

 material which appears to be organic debris though no recognizable remains are noted. 



Station WS 605. 28. v. 31. Lat. 32°os'S. Long. 71° 50' W. 1296 m. (Plate XXII.) 

 Terrigenous mud. A brownish mud, consisting mainly of mineral grains, but with some flocculent 

 matter. The great majority of the grains are less than o-i mm. in diameter. The larger grains in- 

 clude angular fragments of quartz (0-25 mm.), prismatic grains of green and brown hornblende 

 (o-i mm.), flakes of white mica (0-2 mm.) showing strain shadows, grains of staurolite and volcanic 

 glass. Rotaline and textularian Foraminifera, together with sponge spicules are sparsely distributed 

 through the deposit. 



Station WS 610. 30. v. 31. Lat. 31 45' 30" S. Long. 72 01' 30" W. 2500 m. (approx.). 

 (Plate XXII.) 



Diatomaceous mud. This is a light brown mud in which the mineral constituent is subordinate in 

 proportion to the flocculent material. The latter is of the usual indefinite character, but it includes 

 frustules of Coscinodiscus together with occasional fragments of Radiolaria, milioline Foraminifera and 

 sponge spicules. The mineral grains are mostly below 0-05 mm. in diameter, and include fragments 

 of quartz and green hornblende besides splinters of volcanic glass. 



Station WS 616. 5. vi. 31. Lat. 27 08' S. Long. 71 10' W. 1768 m. (Plate XXII.) 

 Terrigenous mud. This deposit has a large proportion of terrigenous material. Subangular grains 

 of quartz up to 0-2 mm. in diameter are preponderant while prismatic grains of brown and green 

 hornblende up to o- 1 5 mm. in length are often seen. The granular flocculent material encloses minute 

 mineral grains and has a greenish hue. Sponge spicules are plentiful, and occasional rotaline Fora- 

 minifera, diatoms (Coscinodiscus) and filaments of green algae are noted. 



Station WS 617. 5. vi. 31. Lat. 27 09' 30" S. Long. 71 15' 42" W. 3031m. (Plate XXII.) 

 Terrigenous mud. Of similar constitution to the deposit from St. WS 616. Detrital grains include 

 angular fragments of quartz (0-25 mm.), prismatic green hornblende, flakes of white mica, and splinters 

 of volcanic glass. A few Radiolaria, sponge spicules, diatoms (Coscinodiscus) and rotaline Foramini- 

 fera occur, but not in sufficient quantity to give character to the deposit. 



Station WS 619. 6. vi. 31. Lat. 27 03' 30" S. Long. 71 30' W. 4864 m. (Plate XXII.) 

 Terrigenous mud. A black fetid mud which has oxidized to a brown colour round the margin of 

 the sample. The black colour appears to be due to dense flocculent aggregates of exceedingly small 

 particles whose precise nature is uncertain. These aggregates enclose a quantity of small, angular 

 mineral grains. The bulk of the sample, however, consists of sand grains, the largest of which are 

 about 0-15 mm. in diameter. The condition of the minerals varies from well-rounded grains to sharp, 



