THE DEPOSITS OF THE SEA-BOTTOM. 6l 



Denmark Strait, so that here the curves approach Iceland, while on the other sides of this island the 

 quartz has to be carried hither from greater distances, and therefore cannot get such a preponderance 

 over the volcanic ingredients. A comparison with the chart showing the distribution of the coarser 

 material, pi. V, will show that this material is much more irregularly distributed than that treated of 

 here. It will be especially conspicuous that the volcanic ingredients among the coarser sizes of grains 

 extended far in tongues towards Greenland, the Faroe Islands, and Jan Mayen, while with regard to 

 the finer ingredients no trace is found of any especial distribution in any of these three directions. 

 This fact must have its origin in the distribution taking place according to different laws in either 

 case; with regard to the coarser material the distribution of the volcanic material out on the two 

 ridges between Iceland and Greenland, and Iceland and the Faroe Islands had to be accounted for 

 by the supposition, that most of this material had been derived from the ridges themselves, what 

 appeared, partly from the large mass of coarser ingredients, partly from the irregular distribution of 

 these ingredients. As to the distribution towards Jan Mayen, on the other hand, the coarser ingredients 

 were here found to a far smaller amount, and without great irregularities of distribution, so that we 

 had to seek another cause of the volcanic nature of these ingredients; this cause might possibly be 

 the distribution with coast-ice and river-ice from Iceland; but on account of my ignorance of the ice 

 in these regions I am not able to value the correctness of this supposition. With regard to the finer 

 ingredients, on the other hand, these more local causes play a rather small part. It is here to be 

 supposed that most of the distribution takes place by means of the currents of material, either eroded 

 from the coast or carried hither by the rivers. It is impossible here to trace the effects of the single 

 currents; on the contrary it would appear, as has been pointed out before, that the material has a 

 power of spreading in directions against the commonly adopted directions of the currents. It would 

 beforehand seem to be almost impossible that for inst. the Icelandic material should be able to spread 

 so far to the south, as it really does, contrary to the direction of the Gidf stream; but now it appears 

 on the contrary that as well the finer as the coarser ingredients reach rather far in this direction; 

 thus we find regions where volcanic and not volcanic material is found to the same amount, situated 

 more than 400 kms. south and southwest of Iceland. Thus the currents cannot be taken to have an 

 especially regular course, but we must suppose them to be, at certain times and on certain localities 

 and depths, interrupted by currents that may have a contrary course. The fact cannot be accounted 

 for by supposing that, to speak only of one region, so small quantities of material are deposited there, 

 that they might possibly have been carried there by quite casual or exceptional circumstances. Some 

 countenance might also be given to this notion by the circumstance, before pointed out, that it also 

 seems to be very difficult to explain by any reasonable cause the presence of the large mass of material, 

 rich in qnartz, south of Iceland. But on the other hand it would be unreasonable to suppose that 

 the two sorts of ingredients could be found so regularly mingled with each other, as they really are 

 in this region, if they were only carried hither by more or less casual and extraordinary circumstances; 

 the fact that we are always able to draw a conclusion as to the composition of any specimen what- 

 ever by regarding the surrounding specimens, tends decidedly to show that certain regularly acting 

 factors must exist carrying both kinds of material to the specimen in question. That we are not able 



