14 0. B. B0GGILD. BOTTOM DEPOSITS. [norw. poi.. EXP. 



possibly come under that designation. As a rule, however, the Transition 

 Clay contains a larger quantity of carbonate of lime than is the case with 

 any of these samples. In the report of the Ingolf Expedition, I have put 

 the limit at 5 per cent, a limit which is rather arbitrary, but which lends 

 itself better to classification than the colour alone, which is generally very 

 difficult to determine. If this classification were adopted, none of the Fram 

 Expedition samples would come under the Transition Clay. Only one sample 

 — No. 12 — has about 4V2 per cent of carbonate of lime; all the others 

 have about 1 — 2 per cent or even less, and thus cannot possibly be said to 

 form any transition to Globigerina Ooze. 



In order to obtain a more complete idea of the mechanical nature of the 

 samples, and thus possibly to find out the laws that govern their distribution 

 upon the sea-bottom, I have subjected some of them to washing. In the 

 case of the samples of this expedition, washing is of comparatively far greater 

 importance than it is generally. The proportion between the various sizes of 

 the particles here, is almost the only thing that causes any considerable diffe- 

 rence between the several samples, whereas in other cases the difference in 

 the quantity of organisms, especially the calcareous organisms, and in the 

 mineralogical components, are of equally great significance in unravelling the 

 complicated conditions that assert themselves in the distribution of the diffe- 

 rent kinds of bottom deposits. 



The washings are accomplished by the aid of a Schoene washing appa- 

 ratus. In detail the same method is followed as in the case of the Ingolf 

 Expedition, with the one exception that the lowest limit for the size of the 

 grains is fixed at 001 mm. instead of at 0"02, principally because the first- 

 mentioned limit is most employed in geological researches, and is thus more 

 practical when it is a question of comparing bottom-samples with other depo- 

 sits. In other respects, if the mechanical nature of the samples be represented 

 graphically, the one of these limits may just as well be employed as the 

 other, and as that of - 02 mm. is much quicker to work with, and certainly 

 also more accurate, it is very doubtful whether it is not to be preferred. 



There is one very important circumstance in connection with the wash- 

 ing, to the clearing up of which my attention during the examination has 

 been very particularly directed, and that is, whether it is possible to make any 

 complete and reliable distinction between the various sized particles in which 



