VIII 



arktiske have ikke kan foregaa saa langsomt som af Jensen 

 formodet. 



Flere af de skalrester, som fandtes paa disse store 

 dyb, giver for en del indtryk af at have været udsat for 

 gnidning. De maa saaledes enten være sti'anslidte eller 

 have faaet afslibningen ved friktion nnder isens bevægelser. 



For de fleste skalresters vedkommende, som toges 

 paa det største dyb, 1333 fv., var kalken i mei-e eller 

 mindre opløst tilstand, saaat adskillige skaller endog ikke 

 kunde opbevares^). Dette, at skallerne saa hurtig synes at 

 opløses paa disse store dyb, tyder paa, at de har været 

 under en kemisk paavirkning, og at de saaledes maa have 

 ligget paa havbundens overflade og ikke været dækket af 

 et beskyttende lerlag. At de derfor i nogen længere tid 

 — geologisk talt — skulde have ligget paa bunden, fore- 

 kommer os lidet sandsynlig. 



Vi tør ikke indlade os i en diskussion, hvorvidt der 

 har fundet en sænkning sted af de arktiske have. Men vi 

 tror ikke, at grundtvandsskallernes forekomst paa de store 

 dyb i Grønlandshavet kan benyttes som et bevis for hypo- 

 thesen. Den strækning, hvor disse skaller er fundne, ligger 

 inden smeltebeltet for store ismasser og naar disse fører 

 med sig større og mindre mængder slam. som sikkerlig 

 skriver sig fra kysterne, ligger det nær at antage, at ogsaa 

 skallerne er ført ud paa dybet ved isen. 



For at faa en tilfredsstillende forklaring paa et fæno- 

 men, som muligens kan faa en større geologisk betyd- 

 ning, vikle det være af interesse, at geologerne nærmere 

 undersøgte de løse stene, som findes paa den havstræk- 

 ning, hvorom der er tale. Muligens vilde en saadan un- 

 dersøgelse give oplysning om, hvorfra de stammer. Under- 

 søgelser af dette slags har tidligere løst interessante geolo- 

 giske problemer. 



') Cfr. John Murray & R. In-ine : On Coral Reefs and other Car- 

 bonate of Lime Formations in Modern Seas; Proc. Roy. Soc. 

 Edinburgh, vol. 17, p. 98. 



decidedly to prove that the formation of sediment in the- 

 arctic seas cannot take place as slowly as Jensen supposes. 



Several of the fragments of shell found at theso 

 greait depths give a certain impression of having been sub- 

 jected to friction. They must thus either have been 

 ground opon the shore, or have acquired this worn appea- 

 rance by fiiction during the moving of the ice. 



In most of the shell-remains tåken at the greatest depth,. 

 1333 fathoms, the lime was in a more or less decomposed 

 condition, so that several shells could not even be pre- 

 served'). The fact of the shells being apparently so rapidly 

 decomposed at these great depths, indicates that they have- 

 heen under chemical influcnce, and must thus have lain 

 upon the surface of the bottom, and cannot have been 

 covered with a protecting layer of clay. It seeras, there- 

 fore, scarcely probable that they have lain there for any 

 length of time, geologically speaking. 



We will not venture on any discussion as to whe- 

 ther a subsidence of the arctic seas has tåken place, but 

 we do not believe that the occurrence of shell-remains from 

 shallow-water in the great depths of the Greenland sea can 

 be used as an argument for this hypothesis. The region in 

 which these shells are found, lies within the melting-zone 

 of great masses of ice, and as these take with them more 

 or less mud that certainly originates on the coasts, it is 

 not unreasonable to suppose that the shells are also carried 

 out iuto deep water by the ice. 



It would be intei-esting, if. in order to obtain a 

 satisfactory explanation of a phenomenon whicii may 

 possibly be of great geological importance. gcologists would 

 examine the loose stønes that are found in this part of 

 the ocean. An examination such as this might possibly 

 give some enlightenment as to whence they come. E.xa- 

 minations of this kind have solved interesting geological 

 problems before now. 



'■) Cfr. John Murray & R. Irviiie: On Coral Reefs and other Car- 

 bonate of Ijime Formations in Modern Seas; Proo. Roy. Soc. 

 Edinburgh, vol. 17, p. 9S. 



