70 THE DEPTH AND MAEINE DEPOSITS OF THE PACIFIC OCEAN. 



clase, luigite, olivine (?), volcanic glass, a little magnetite, a few manganese 

 grains, and one or two flakes of hematite. 



Fine Washings (24.75 per cent), very flocculent brown clay, with 

 numerous but extremely minute mineral particles. 



No. 50. Station 4531,* 6th February, 1905. 

 Lat. 21° 4.5' S. ; long. 133° 1.2' W. ; depth, 2225 fathoms. 



CALCAREOUS MUD : light brown, slightly coherent, powdery, containing 

 no macroscopic elements. 



Calcium carbonate : 72.72 per cent, many very minute coccoliths and 

 Tunicate spicules, together with a large quantity of calcium carbonate, prob- 

 ably of organic origin, but so finely comminuted that no structure can be 

 recognized under the microscope. 

 Residue : 27.28 per cent : — 



Siliceous Organisms, per cent. 



Minerals (0.1 per cent), principally manganese grains somewhat under 

 0.1 mm. in diameter; most of the other particles are microscopic, a few at- 

 taining a diameter of 0.1 mm. ; the only one that can be specifically deter- 

 mined is phillipsite, in the form of clusters ; one or two particles appear to 

 be volcanic glass. 



Fine Washings (27.18 per cent), brown clay, darker in hue than the 

 deposit itself, colored by the oxides of iron and manganese ; no siliceous 

 organisms can be seen, and the very rare mineral particles present are much 

 too small to be determined. 



No. 51. Station 4532,* 7th February, 1905. 

 Lat. 18° 29.4' S. ; long. 130° 50.8' W. ; depth, 2319 fathoms. 



RED CLAY : very dark brown, nearly black, very plastic and sticky, soft 

 and clayey to the touch. 



Calcium carbonate : 18 per cent, pelagic and bottom-living Foramini- 

 fera, and Fishes' teeth. 



Residue : 82 per cent : — 



Siliceous Organisms (small traces), only a few fragmentary arenaceous 

 Foraminifera and Sponge spicules. 



Minerals (small traces), principally manganese grains, 0.1 mm. in di- 

 ameter, a few angular splinters of colorless glass, and phillipsite in isolated 

 crystals and twins. 



