VII 



det løse slami). Vi skulde derfor antage, at det kun er 

 det øverste bundlag, som er bleven afflødt. 



Dr. Jensen antager, at sedimentærdannelsen paa de 

 store havdyb foregaar overmaade langsomt, idet han støtter 

 sig til John Murrays iagttagelser fra Challengerexpeditio- 

 neu. De arktiske have frembyder imidlertid ikke de samme 

 fysikalske forholde som de store verdenshave. Enhver, der 

 har bereist de arktiske egne. vil have seet, at isen fører 

 adskillig slam med sig. Pa Nordhavsexpeditionen saaes 

 oftere mere eller mindre skiddeu is og de samme iagttagel- 

 ser gjorde Nansen i Danmarksstrædet. 



Konservator Kolthoff fortæller i ,.Ur Djurens Lif" 

 (vol. 2, p. 457), at tre klapmyds (ci/gtopliora cristata)^ 

 som blev skudt paa en plads, hvor havet var melleni 2 

 og 3 tusen meter dybt, havde lerslam i maven. To af 

 dem havde maven fuld deraf Dette slam maa dyrene 

 have slikket i sig ude paa drivisen, thi det er utænkeligt, 

 at de kunde dykke ned til bunden paa et saadant dyb; 

 Heller ikke er det tænkeligt, at de kan have faaet det 

 sig inde ved land, da dette var for langt fjernet og denne 

 sælart desuden holder til ude paa drivisen niellem Spits- 

 bergen, Jan Mayen og Grønland og kun sjelden træfies 

 den under land eller i fjordene. 



Tager vi for os Schmelcks arbeide over havbundens 

 afleirninger-), vil vi finde, at der var sand og smaasten ^ 

 bundprøverne fra en hel del dybvandsstationer fra Spits. 

 bergen nedover mod Island og paa vedføiede kart har v 

 afsat sydgrænsen for disse stationer. Som det vil sees 

 falder den paa en paafaldende maade sammen med grænsen 

 for isens smeltebælte. I bundprøverne fra stationerne nord 

 for denne linie var der sand og grus, syd for linien fandtes 

 derimod kun lerslam. Først fra stationerne ind under 

 kystbankerne gjennnder vi igjen grus og sand. Af disse 

 stationer med sand i bundprøverne ligger station 240 og 

 243 indenfor Ingolfe.xpeditionens undersøgelsesfelt. 



En ganske interessant bekræftelse paa det rige ma- 

 teriale, som isen maa sprede over sit smeltefelt, fik vi ved 

 at faa anledning til at se en planktonprove som kandidat 

 Wollebæk havde tåget under et togt med ,,Heimdal" vaareu 

 1900 i nærheden af iskanten paa 70" 24' N. Br., 42" 29' 

 0. Lg. Dybde 50 fv. Planktonprøven toges midtvands 

 paa 25 fv. I denne fandtes en paafaldende mængde sand- 

 korn samt ikke saa faa smaa skalrester. Alt dette synes 

 paa det bestemteste at vise, at sedimentærdannelsen i de 



') Jensen antager at trawlen kan trænge indtil 2 fod (02 era.) ned 

 i bunden. Saa svagt, trawlnettet paa Nordhavsexpeditionens var 

 belastet, holder vi dette for usaudsynlig. 



^) Nordhavs Exp., Kemi. 



the soft mud'. We should therefore suppose that it is 

 only the ujjpcrmost layer of the bottom that has been 

 skirn med. 



Ur. Jensen assumes that the formation of sediment 

 in the great ocean depths takes place exceedingly slowly, 

 supporting his assumption on John Murray's observations 

 on the Challengér Expedition. The arctic seas, how- 

 ever, do not present the same physical conditions as the 

 large oceans. Every øne who has travelled in the arctic 

 regions will have seen that the ice carrios a consider- 

 able quantity of mud with it. Ice that was more or less 

 dirty was frequently seen on the North Atlantic Ex- 

 [«■(lition, and Nansen oi)served the same thing in Denmark 

 Strait. 



Cui-ator Kolthoff, in his 'Ur Djurens Lif (vol. II. 

 p. 457) relates that three hooded seals (Cystophora cri- 

 stata) that were shot in a place where the sea was be- 

 tween two and three thousand metres deep, had clayey 

 mud in their stomaeh, two of them being quite filled 

 witli it. The animals must have licked u]) this mud 

 out on the drift-ice, for it is impossible to imagine that 

 they could dive down to the bottom at such a depth. 

 Noi- is it likely that they can have swallowed it on shore, 

 as this was too reniote; and raoreover this species of seal 

 lives out on the drift-ice between Spitsbergen, Jan Mayen, 

 and Greenland, and is rarely found near the shores or in 

 the fjords. 



If we look at Schmelck's report on the ,,Oceanic 

 Deposits"^), we find that there were sand and small stones 

 in the bottom-samples from a number of deei)-water sta- 

 tions, from Spitsbergen southwards towards Iceland. In 

 the accompanying map, we have marked the southern 

 limit of these stations. It will be seen that this coin- 

 cides in a remarkable manner with the limit for the melt- 

 ing of the ice. In the bottom-samples from the stations 

 north and west of this line, there was sand and gravel; 

 south and east of it. on the other hand. there was only 

 clayey mud. It is only at the stations in under the coast- 

 banks that we once more find gravel and sand. Among 

 the stations with sand in their bottom-samples, Stations 

 240 & 243 are within the field of the investigations of 

 the Ingolf Expedition. 



We had a most interesting proof of the abundance 

 of matter that the ice must scatter over its melting area, 

 in seeing a plankton-saraple tåken by Hr. Wollebæk 

 during a cruise with the 'Heimdal' in the spring of, 

 1900, near the edge of the drift-ice in 70° 24' N. Lat. 

 and 42" 29' E. Long., depth 50 fathoms. The planktou- 

 sample was tåken in midwater at 25 fathoms. A remarkable 

 nundier of sand particles were found in this sample, and 

 not a few small fragments of shell. All this goes most 



') Jensen assiimes that the trawl can penetrate as much as 2 

 feet (62 cm.) into the bottoiti. So IJghtly was the trawl-net on 

 the North Atlantic Expedition loaded, that we considcr this im- 

 probable. 



*) North Atlantic Expedition, Chemistry. 



