THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 45 



Calcium carbonate : 20.46 per cent, Foraminifera, mostly Globigerin- 

 ida3, the individuals being of very small size, but in a good state of preser- 

 vation, and Echinbid spines. 



Residue : 79.54 per cent, earthy brown in color, and very fine grained : — 

 Siliceous Organisms (3.5 per cent) ; Radiolaria are very abundant and of 

 large size, and form the greater part of the heavier portion of the residue. 

 There are also a good many Diatoms, and some Sponge spicules. 



Minerals (traces) ; the mineral particles are so small and few in number 

 that they cannot be all identified. Magnetite, hematite, quartz, and a little 

 glauconite could be recognized. Particles having the appearance of horn- 

 blende, augite, and zircon may be mentioned, but their identification is very 

 doubtful. 



Fine Washings (76.04 per cent) ; gray, somewhat brownish, matter, very 

 clayey, containing a great number of Diatoms, together with a few Sponge 

 spicules and minute mineral particles. 



No. 7. Station 4654, 12th November, 1904. 

 Lat. 5° 46' S. ; long. 81° 31.9' W. ; depth, 1036 fathoms. 



GREEN MUD : dark green, very plastic and smooth to the touch, drying 

 into hard, coherent lumps. The dried material, powdered in a mortar, has 

 a vivid light-green color. 



Calcium carbonate : traces ; with acid the deposit gives hardly any 

 effervescence, and only one or two pelagic Foraminifera could be detected. 



Residue : 100 per cent : — 



Siliceous Organisms (traces), only one or two Sponge spicules and 

 Diatoms. 



Minerals (12.5 per cent), angular and rounded, mean diameter 0.15 

 mm. ; of terrigenous minerals the most common are quartz and felspar. Of 

 the latter, two varieties appear to co-exist : some fragments have the optical 

 properties of an oligoclase containing 30 per cent of anorthite ; others be- 

 long to bytownite. Both these are in fairly large crystals, but, besides, there 

 are many microlites belonging presumably to oligoclase. One or two small 

 fragments of colorless volcanic glass are also present. Magnetite is repre- 

 sented in very small amount, and so also is white mica, in scales that have 

 lost much of their transparency. A mineral not often met with, namely, 

 chalcedony, is also to be seen, as small rounded fragments exhibiting the 

 phenomenon of the black cross between crossed nicols in parallel light. 



