CHARACTERS OF THE MATERIAL RECEIVED 7 



387, 391, 394, 432A) lie in the western end of this elUpse, and the remainder of it is 

 probably an unknown quantity so far as bottom deposits are concerned. 



As regards the foraminiferal fauna of the two deposits, there appears to be little 

 difference between the Blue Mud and the Blue Mud approximating to Red Clay. The 

 number both of species and specimens decreases enormously, as might be expected 

 considering the greater depth and distance from the Antarctic coast-line, but setting 

 aside the stations on the continental slope, where the foraminiferal fauna is abundant 

 and varied as it usually is on such slopes, there are many stations in the Blue Mud area 

 with approximately similar faunal lists to those of the stations in the area of the Blue 

 Mud approximating to Red Clay. 



Pirie's description of the two deposits is worth extracting, especially as he deals with 

 the material from a mineralogical standpoint, while any remarks of mine are necessarily 

 of a faunistic character. 



Blue Mud. A typical specimen from the sounding tube has the following characteristics. It is of 

 a greenish-grey or bluish-grey colour and is a coherent, moderately tough mud with a sufficiently 

 clayey character to give it an unctuous feeling, but when rubbed between the finger tips one can 

 always feel some gritty particles. When dried it is of a light grey colour and has a slightly clayey 

 odour when breathed upon, and is capable of taking a lustrous polish when rubbed on the finger nail. 

 There is never any smell of sulphuretted hydrogen as in many terrigenous muds. Of CaCOg there is 

 in most cases none, but every now and again a certain amount occurs, varying from a mere trace up 

 to 6 per cent. This is from the shells of Foraminifera.. . . Siliceous organisms are extremely rare; 

 they may be entirely absent or there may be from a trace up to 1-2 per cent; and these are chiefly 

 sponge spicules and fragments of Radiolaria, very rarely diatoms. 



Mineral particles over 0-05 mm. in diameter form 10-20 per cent of the deposit; the majority are 

 angular in shape but the larger fragments up to 2 or 3 mm. in diameter are generally sub-angular, and 

 occasionally glacial striae may be detected on them. Quartz grains predominate largely, but a great 

 variety of other minerals occurs. Glauconite is rare, being only found as casts in a few of the samples 

 in which there are calcareous Foraminifera. Manganese is common as a thin pellicle over other 

 mineral particles, and a few very small grains occur, but there are no nodules such as are found in the 

 abyssal Red Clays. 



The remainder of the deposit is made up of "fine washings". When examined microscopically 

 this part is found to contain occasional fragments of siliceous organisms, and a small amount of true 

 amorphous clayey matter, but it largely consists of minute mineral fragments under 0-05 mm. in 

 size, the majority being probably between 0-02 and 0-005 n^ni- These represent the rock flour pro- 

 duced by the abrasive action of the Antarctic ice-sheets ; this is carried out to sea partly in the ice of 

 the icebergs, but no doubt largely also suspended in the water.. . .The trawl usually brought up a 

 large quantity of mud and rocks. The latter vary in size from fine gravel up to boulders weighing 

 over two cwts. . . . Some of the rock specimens have part of their surface clear and part coated with 

 manganese ; the shape indicates that the latter part must have been embedded in the mud, while the 

 former projected out into the water. ... It is noteworthy that only one whale's ear-bone was brought 

 up. As whales are probably quite as numerous, if not more so, in this area than in the Red Clay area 

 of the Pacific, the explanation can only be that they are buried by the rapidity with which this 

 deposit is accumulating, as contrasted with the extreme slowness of the Red Clays 



Blue Mud approximating to Red Clay. The area . . . approaches Red Clay in many of its characters. 

 The colour is more of a brownish-grey than the blue or green grey of the typical Blue Mud ; it is 

 more tenacious and clayey, and it is not so easily rubbed down for microscopic examination, but still 

 much more easily than a typical Pacific or Atlantic Red Clay. The mineral particles average only 

 about 3 per cent, of which a considerable number are of volcanic origin, but too much reliance cannot 



