OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 683 



a few glacial striae are to be seen ; but sub-angular and angular particles are just as 

 common. 



The majority of the grains, like the larger rock specimens, are of "continental" 

 origin — quartz, felspar of various kinds, and green hornblende being the commonest. 

 Fairly common also are biotite and magnetite, many others in less abundance. 

 Volcanic glass and minerals of volcanic origin are widespread, although not abundant ; 

 they are distinctly relatively more numerous in the specially clayey deposits in the 

 part of the Weddell Sea furthest from land, and it is noteworthy that these same 

 samples show the presence of a little palagonite — a point in which they resemble the 

 abyssal Red clays. Philippi points out that the absence of palagonite from these 

 deposits is one feature of distinction from the Red clays, he not having found any in 

 his samples. The palagonite particles I have seen are certainly very small, nothing, 

 in size or amount, like those in which it occurs in the true Red clays, and it is only 

 present in a few of the samples from the deepest portions of the Weddell Sea, and 

 those furthest from land, where the deposit is of more pronouncedly clayey character. 



Manganese is common as a thin pellicle or coating staining the surface of many of 

 the rocks and smaller mineral particles of a brownish colour ; but manganese nodules, 

 such as occur so plentifully in the Red clays, do not occur. A few small manganese 

 grains occur iu some of the samples, but only of minute size and very sparingly. 



Glauconite is present in a few samples, but also very sparingly, and when present is 

 usually in the form of casts of foraminiferal shells. 



Fine Washings. — The composition of the " fine washings," i.e. that portion of the 

 deposit which is removed by the first decantation after the sample has been completely 

 broken down into its constituent parts by stirring and rubbing in a considerable 

 quantity of water, is one of the most characteristic features of the glacial marine 

 deposits. They are to a very large extent made up of minute mineral fragments, the 

 finest " rock flour " produced by the abrading action of the Antarctic inland ice, although 

 there is also always a certain amount of amorphous clayey material. These are 

 practically the only two constituents of the fine washings of the glacial deposits, 

 particles of siliceous organism being so scanty as scarcely to come into consideration. 

 In my estimate of the amount of fine washings I include under the heading of " Minute 

 Mineral Particles" everything under 0'02 mm. in diameter along with a certain variable, 

 but usually small, amount of those between 0'02 and 0*05 mm. In twenty-nine samples 

 the average percentage of the fine washings is 82. Two samples (Nos. 21 and 

 26a, one a sandy deposit from 1775 fathoms ; the other a deposit bordering a Diatom 

 ooze) give a figure of under 30; six of 95 per cent., or over: all samples from that 

 portion of the Weddell Sea furthest from the Antarctic continent ; the remainder are all 

 between 75 and 90. An estimate was made — it is nothing more — that if under the 

 heading " Mineral Particles" all particles down to 0*005 mm. were included, the average 

 percentage of these would be nearer 70 than 167, as it is recorded; and even then the 

 remaining fine washings would not be all amorphous clayey matter, but would still 



