648 J)R J. H. HARVEY PIRIE ON DEEP-SEA DEPOSITS 



designated " fine washings " ; this portion contains amorphous and clayey matter, 

 minute mineral particles mostl}^ under 0*02 mm. in diameter and always less than 

 0"05 mm., and some of the siliceous organisms. In the next decantations siliceous 

 organisms, if they are present, predominate ; but some of the lighter mineral particles, 

 between 0'05 and 0"02 mm. in diameter, will also be found. The heavier minerals, 

 including practically everything over 0"05 mm. in diameter, remained behind after all 

 the lighter material had been decanted off. Each of the decantations was allowed to 

 settle down in a basin and the material was then submitted to microscopic examination. 

 The percentage of the heavier minerals was frequently checked by weighing and 

 comparison with the weight of the original sample ; but as some allowance had always to 

 be made for the lighter minerals carried off in the second decantations, the percentage 

 figure given for " minerals " can only be regarded as an estimation — in most cases, 

 however, probably a fairly accurate approximation of the amount over 02 mm. 

 in diameter. The figures given for the percentages of siliceous organisms and of "fine 

 washings " are, of course, also only approximate estimates ; but as the routine followed 

 in every case was the same, they may safely be taken, if not as absolutely accurate, at 

 least as of fairly accurate comparative value. 



Where a sample contained calcareous organisms, a similar rubbing-down process 

 was gone through with a specimen unattacked by acid, so that the foraminifera and 

 other calcareous organisms might be sorted out. All foraminifera picked out from 

 deposits at any stage (and in a number of instances also original samples of deposit 

 for separation) were sent to Mr F. Gordon Pearcey for examination, and I am 

 indebted to him for the identification of those which are referred to in this report. I 

 have also to express my indebtedness to Sir John Murray for instruction in the 

 Challenger office in the general methods of examining deep-sea deposits ; to Professor 

 James Geikie of the University of Edinburgh, in whose laboratory the examination 

 of the material was carried out ; to his assistant, Dr Campbell, for help in identifica- 

 tion of minerals and rock specimens ; and lastly, to the University of Edinburgh for 

 a grant from the Moray Research Fund for expenses connected with the work. 



Material Available for Examination. 



Of the fifty-five samples brought home by the Scotia, one (No. 1) comes from the 

 tropical portion of the S. Atlantic, namely from the Abrolhos Bank, off" the coast of 

 Brazil, and, more especially since it is fragmentary in character, needs no further 

 description than that given in the systematic account of the samples. One (No. 2) 

 is a typical terrigenous mud from the shallow water of Stanley Harbour in the 

 Falkland Islands. One (No, 29) is from a depth of 56 fathoms on the Burdwood Bank, 

 lying to the south of the Falkland Islands. Five samples (Nos. 24a, 246, 24c, 25a, 

 256) are from depths of under 100 fathoms, in close proximity to the land of the 

 S. Orkney Islands, whilst 2 others (Nos. 22 and 23) are from just over 200 fethoms not 



