APPENDIX. 



NOTES ON THE EXAMINATION OF MATERIALS FROM STATION 2 

 (1899-1900 CRUISE) AND STATION 4719 (1904-1905 CRUISE). 



A. Palagonitic Tuff from Station 2, 2368 fathoms. 



B. Red Clay from Station 4719, 2285 fathoms. 



A. PALAGONITIC . TUFF from Station 2, 2368 fathoms. 



At the suggestion and under the direction of Sir John Murray, this substance, which is 

 somewhat of a novelty in deep-sea deposits, was submitted to a special investigation. 



The tuff was brought up in large blocks and slabs, some of them the size of a bucket. 

 It is of a creamy-white color and rotten consistency, crumbling to a floury powder when 

 rubbed. Interspersed in the mass are numerous minute grains of black manganese, a thin 

 deposit of which also covers the irregularly mammillated upper surfaces. Most of the 

 blocks have been much bored by worms, and the tunnels thus formed have silted up with 

 Red Clay. 



Viewed under the microscope, it appears as an apparently amorphous substance of very 

 loose texture, with no features, apart from specks of manganese, to interrupt its homoge- 

 neity, except a few casts of Glohigerina shells. The casts occur very rarely, but are re- 

 markably well formed when they do occur ; the internal and external casts are of the same 

 material, and between them the shell itself has been dissolved out, leaving an empty space, 

 across which run innumerable threads of the casting matter, corresponding to foramina 

 which have been filled up. Under a high power, the crushed substance is seen to consist 

 of transparent particles, mean diameter about 0.005 mm., many of which are of parallel- 

 sided or prismatic habit, though indisputably crystal! ographic contours could not be de- 

 tected. Micro-sections show an intricately felted, homogeneous network, at the boundaries 

 of which can be perceived aggregations, which have broken loose from the mass, strongly 

 resembling twinned prisms. On the whole, the substance seems to have a subcrystalline 

 character. 



Moistened with water, the substance loses coherence and turns to a pale yellowish- 

 brown color. On drying, it resumes its whiteness ; it does not bake hard, and can be 

 crushed by the fingers even after exposure to dull red heat. It is therefore not of the 

 nature of a clay. 



By elutriation with water, followed by separation with bromoform, some particles of 

 undecomposed minerals can be extracted. They are present to the extent of fairly exactly 

 1 per cent, have a mean diameter of 0.15 mm., and consist for the greater part of oligo- 

 clase, which is mostly in very fresh condition ; there are also green tabular splinters of 

 volcanic glass, an unidentified mineral (olivine?), which has decomposed to a red amor- 

 phous body, and a little magnetite. 



