14 DISCOVERY REPORTS 



I have not preserved a note of their frequency at that station, but beheve they were 

 fairly common. At St. 226 they are abundant and variable in size up to 0-3 mm. 

 (300 /x) in length of edge; some twinned and multiform specimens were also noted. At 

 St. 290 they are abundant but small — average length of edge probably less than o-i mm. 

 (loofji). At Sts. 295, 300, 303 and 387 they were very rare, and of small or average 

 size. All the stations are in the very deep water of the Central Weddell Sea, and in 

 both Blue Mud and Blue Mud approximating to Red Clay areas. None were seen at 

 the inshore stations. It is, however, quite possible that the crystals occur elsewhere, 

 for owing to their size, shape and generally glassy transparency, they would be easily 

 overlooked among other mineral grains. 



From the fact that the edges are invariably sharp and unbroken I have no doubt that 

 this mineral, hitherto unknown in deep sea-deposits, is formed in situ. 



The crystals of calcium sulphate or gypsum are frequent in the residues at Sts. 387, 

 391 and 428, rare at Sts. 290 and 422. Sts. 387 and 391 are in Pirie's Blue Mud ap- 

 proximating to Red Clay area, the others in the Blue Mud area, but all are far from land 

 and in great depths, 2500-2715 fathoms. The crystals are similar to those which I have 

 found abundantly in Gault and other fossil clays, and I have never previously seen them 

 in a recent deposit. It is stated by Murray and Hjort (M. and H., 1912, DO, p. 176): 



From what is known of the solubiHty of gypsum in brines, and allowing for the excess of SO4, one 

 would suppose that sea-water is very nearly saturated for this salt, and that addition of, for instance, 

 a sulphate would precipitate it. But gypsum is unknown as a constituent of deep-sea deposits (unless 

 of extraneous origin), so that its solubility-limit is evidently never exceeded under submarine con- 

 ditions. 



From the condition of the crystals, which show little signs of disintegration, the dis- 

 tance of these stations from the Antarctic coast-line, and the fact that I have not ob- 

 served any gypsum at the many stations nearer that line, it is difficult to believe that the 

 mineral has not been formed in situ. The formation of the crystals may perhaps be 

 evidence that the deposits in the Central Weddell Sea are accumulating very slowly, 

 in spite of the evidence to the contrary afforded by the absence of whale's ear-bones 

 noted by Pirie (see ante, p. 7). 



A third crystalline component in nodular form has been identified as calcium citrate ; 

 it is common at St. 417, but was not observed elsewhere. 



CORRECTED CONCLUSIONS TO BE DRAWN 

 FROM THE RECORDS 



As a result of my examination of the Scotia material many of the conclusions drawn 

 from Pearcey's report on the same material published in the previous report (A, pp. 10- 

 12, 23-5) require drastic revision. It was assumed on the basis of his lists that the for- 

 aminiferal fauna of the Weddell Sea was relatively scanty and of a cosmopolitan deep- 

 water character ; that it was isolated and had little in common with the fauna found to 

 the west of the line of the Scotia Arc ; and that there was practically no evidence of 

 Pacific influence in the sea. 



