360 f Miscellaneous. ^, 



betoken ? The question is an intricate one, and so far as our present 

 information goes does not seem to admit of a perfectly satisfactory 

 solution. This much may be said, however, that their presence on 

 the immediate surface-layer of the sea-bed is only reconcilable with 

 one or other of the following suppositions :-:— They must either have 

 been recently dropped by some means from the superincumbent 

 waters, have been deposited by floating ice during jSast periods of 

 the earth's history, must occur in bods which were once exposed 

 above the surface of the sea, or be drifting about the bottom through 

 the action of ourrents. 



" Now in no case hitherto recorded have these stones been of large 

 size, probably not larger than a hazel-nut * ; but they present un- 

 doubted traces of attrition. Fish, as is well known, sometimes 

 swallow small stones and, as a matter of course, get rid of them in 

 time ; but this would not meet the requirements of the first of the 

 above suppositions, inasmuch as it is obviously improbable that so 

 many fisla with stones in their stomachs should be moving about the 

 ocean as would be necessary to account for the fact. It is still more 

 improbable, if not impossible, that fish could have conveyed such 

 substances from the distant shores where they are alone obtainable. 

 So that, viewing this circumstance in conjunction with the fact that 

 no floating ice now-a-days traverses the areas referred to, it is certain 

 the matter is inexplicable on the first supposition. 



" If deposited from floating ice during 'past periods of the earth's 

 history (according to the second supposition, which is by no means 

 impossible), it follows as an inevitable consequence that the muddy 

 deposits are local in character, and that certain areas of the sea- 

 bed consist of bare rock, or that they are swept away by currents 

 as fast as they are produced. I regard the first of these causes as 

 most conformable with the evidence ; for although there is reason 

 to believe that deep-seated currents prevail with sufficient force, in 

 some of the shallower tracts of the Atlantic, to move the fine particles 

 of which these deposits are for the most part composed, there is no 

 ground whatever for supposing that they are ever powerful enough 

 to sweep along large objects such as the stones of which I have been 

 speaking f. It will be seen, therefore, that we are justified in laying 

 stress on the possibility that extensive areas of exposed rock may 

 occur along the basin of the Atlantic, which have hitherto escaped 

 deteetiou. The third and fourth suppositions are thus disposed of 

 likewise." {Loc. c\t. p. 39.) 



As it is stated in the number of the 'Athenaeum ' already referred 

 to by me that Mr. Gwyn JeflEreys's paper is to be hereafter repro- 

 duced in the ' Proceedings ' of the Royal Society, I beg leave to 

 bring the above facts and observations to his and your readers' 

 notice. I remain, Gentlemen, 



Your very obedient Servant, 



September 19, 1876. G. C. Wallich. 



* This is not quite accurate. As stated in 'The North-Atlantic Sea- 

 Tied,' p. 3, the piece of granite to which the dead Serpula is attached 

 measures about an inch square. 



t See ' North- Atlantic Sea-bed/ pp. 4-7. 



