22 THE DEPOSITS OF THE SEA-BOTTOM. 



mineral particles, carried out into the sea, the coarsest accordingly, as was to be expected, precipitate 

 proportionally quickly, while the finest are carried farthest away; if we had specimens from a still 

 greater distance from the land, these specimens would probably come up very close to ioo per ct. 



If we, however, examine the circumstances more in detail, a number of irregularities will ap- 

 pear; these irregularities are most conspicuous in the percentages of the coarsest ingredients over 

 o-5 ram , in which numbers an exceedingly great variation is seen. While the average numbers with 

 regard to the three species of deposits were 4-17, 3-44 and 090, we find that more than half of all the 

 specimens have percentages under o-i, while about two thirds have under 1. Thus it is seen that 

 the high average numbers arise from a comparatively small number of specimens, which are, how- 

 ever, tolerably equally divided between the three species of deposits. Of the 24 specimens having 

 more than 1 per ct, two are found at Jan Mayen, three at the west coast of Greenland, south of 

 Cape Farewell, two at the southwest coast of Iceland, and only three, the specimens 19, 65 and 105, 

 are, without any apparent reason, found far out in the Atlantic. All the others are found on or im- 

 mediately south of. the submarine ridge between the Faroe Islands and Iceland, and just south of the 

 ridge between Iceland and Greenland, and thus it is an obvious conclusion that this coarser material 

 for the greater part is derived from these ridges themselves. On the ridge between Iceland and the 

 Faroe Islands we find the very characteristic fact that the specimens on the ridge and immediately 

 south of it have the very great percentages, while the specimens immediately north of it have only 

 very small amounts, which fact is seen by far most plainly in the eastern part, where the specimen 

 143 on a depth of 388 faths has a percentage of 3138, the absolutely largest percentage found in any 

 of the specimens, while the specimens 138 and 141 a little farther north on depths of 471 and 679 

 faths, have 0-23 and 076 per ct, and the specimens 139 and 140, situated immediately north of the 

 two preceding, on depths of 702 and 780 faths, only have the percentages 0-02 and 0-05. From these 

 facts we should seem to be justified in drawing the conclusion that currents are passing over the 

 ridge, chiefly from north to south; that currents are likely to pass in the same direction over the 

 ridge between Iceland and Greenland would also seem to be a lawful conclusion on account of the 

 large mass of coarse material found on the route south of this ridge; here, however, specimens farther 

 north for comparison are wanting. 



As the presence of the coarser material may almost always be sufficiently accounted for by 

 the proximity of the coast or one of the mentioned ridges, there is thus no reason to suppose that 

 the ice-bergs have been of any considerable importance with regard to the deposition of this material. 

 On the contrary, in places where at times many icebergs are found, as in the tract north of Iceland 

 and west of Greenland at the 65 th degree of latitude, very small masses of coarser material are seen 

 in the specimens, as will appear from pi. Ill; the northern coast of Iceland is even the place where 

 the curves are closest to the land in the whole territory. From this we may be almost justified in 

 concluding that ice-bergs can not generally produce till-like deposits, as has been supposed in earlier 

 times, a supposition scarcely quite given up in our time. On the other hand, the icebergs may, of 

 course, have contributed some part of the coarser material found in the different specimens; but when 

 a survey of the map shows the specimens south of Iceland outside of the region of the ice-bergs to 

 contain the same masses as those between Iceland and Jan Mayen, we shall necessarily arrive at the 



