53 



meget ubetydelig Va -t og riml (i tørret Tilstand) paa Vand 

 ligesom Pimpsten. 



Den indvendige røde Substans var at føle paa som 

 meget fint Mel og smuldrede let hen ved Berøring. Hen 

 havde følgende Sammensætning : 



Paa Grund af sin ujevne Funn og ubetydelige Vægt 

 havde disse Klumper ved det første Øiekast megen Lighed 

 med Pimpstene, men den nærmere Dndersøgelse viste dog, 

 at de forøvrigt var meget forskjellige frå disse. Intet 

 sammenhængende Kiselskelet kunde paavises, og livad der 

 ved første Blik kunde antages for Blærerum. befandtes ved 

 Eftersyn kun at være Huller efter Anneli der. der isærdeles- 

 hed paa Overfladen havde gravet sig talrige Gange. Den 

 indre rode Substans bestod vistnok for en Del af amorft. 

 vulkansk Glas. men dette forekom i friske Splinter eller 

 Stykker af et lignende Udseende. som det af Yulkaneme 

 udkastede Pimpstenspulver. 



Jeg er dog tilbøielig til indtil videre at fastholde den 

 Tanke, at diss? Klumper kan have sin Oprindelse fra Pimp- 

 stene. der har gjennemgaaet betydelige Forandringer paa 

 Havbunden, hvor de har virket som et Filtrum for det 

 gjennemstrømmende Vand. 1 )et kan muligens tjene til Op- 

 lysning om denne Våndets Bevægelse paa Havbunden. at 

 alle Furer eller Revner i de ovennævnte Klumper var del- 

 vis fyldte med Skaller af Globigeriner. 



Paa Stat. 40 fandtes som sagt ogsaa en Del Stykker 

 af umiskjendelig Pimpsten. der imidlertid var af en meget 

 løs og usammenhængende Konsistens. 



Fortiden de ovenomtalte Klumper optoges paa samme 

 Sted ogsaa andre, der var mindre end hine og forøvrigt af 

 et ganske forskjelligt Udseende. Xogle af disse bestod af 

 en hvid Substans, der havde megen Lighed med Kaolin. 

 En mikroskopisk Undersøgelse viste, at den indeholdt en 

 .M;t'iigde Kiselskaller af Diatomeer. Andre havde Form af. 

 flade Stykker og bestod af et mørkgrønt, tint Ler med en- 

 kelte gulhvide Baand. Den fjerde og .sidste Slags var 

 dannet af en tin og fast, gulhvid Substans, der i Udseende 

 nærmest kunde sammenlignes med haard. hvid Ost. I de 

 to sidstnævnte Arter opdagede jeg under Mikroskopet nogle 

 enkelte Diatomeer og blot faa Splinter af vulkansk Glas.- 



Det synes altsaa. som om vi her paa en af Expedi- 

 tionens sydligste Stationer har fundet Dannelser af lignende 

 Art som de. der omtales af John Murray i "Reports from 

 the ('ballenger". 



1 Da denne røde Substans ogsaa Lndeholdi noget Mangan, der 

 ikke blev bestemt, kan maaske Tabet ved Analysen hidrøre derfra. 



trilling, and they float (in a dry state) on the surface of 

 water, like pumice. 



The red inner substance, which crumbled to the touch, 

 became impalpable as the finest Hour on being reduced to 

 powder. lts chemical constituents were as follows: — 



Loss by ignition . . 14.4t> 



( )xide of iron . . . 2H.15 



Alumina 14.14 



Magnesia .... 1.38 



Silicic acid .... 4n.4.~> 



96.58 1 ' 



By reason of their irregular form and incohsiderable 

 wgight, these eoncretions had apparently much in common 

 with pumice: but a closer examination showed them to be 

 essentially different from that substance. No siliceous skele- 

 ton could be detected. and what at the first glance miglit 

 have been tåken for vesicular cavities. proved to be the 

 work of Anuelids. which. from the surface in particular, 

 had excavated nia ny of their passages. The red-coloured 

 inner substance did not indeed partly consist of scoriæ, but 

 this constituent occurred in the form of minute splinters or 

 particles. similar in appearance to the pumice-powder 

 ejected by volcanoes. 



Meanwhile, I am most inclined to regard these eon- 

 cretions. till further light shall have been thrown on their 

 phenomenal occttrrence. as the product of pumice, which. 

 from ha ving acted as a percolating medium for water fiow- 

 ing over the sea-bed. has undergone partial transformation. 

 As a feature in some measure perhaps explanatory of the 

 conditions determining the motion of such water, I can add 

 that all furrows and crevices in the said eoncretions con- 

 tained shells of Gldbigerinæ. 



At Station 40. as previously stated, the dredge brought 

 up a few pieces of unmistakeable pumice, exceedingly po- 

 rous however and friable. 



Exclusive of the above-described eoncretions, others 

 of a smaller size and widely different appearance came up 

 in the same locality. Some of these consisted of a white 

 substance presenting considerable resemblance to kaolin, 

 which. on being examined under the microscope. was found 

 to eontain great numbers of the siliceous shells of Diatoms. 

 Others were lamellar in form, and consisted of a fine dark- 

 green clay marked with a few yellowish-white bands. A 

 fourth kind — the last - were formed of a fine and firm 

 yellowish-white substance. in appearance very like hard, 

 white cheese. The two last-mentioned kinds of eoncretions 

 exhibited under the microscope divers isolated shells of 

 Diatoms and a very few splinters of scoriæ. 



Hence it would appear that the Norwegian Expedition, 

 at one of its most southerly observing-stations. met with 

 formations similar to those described by Mr. John Murray 

 in "Reports from the 'Ghallenger'." 



1 The red-coloured part of the eoncretions having also contained 

 mangranese, this constituent is possibly comprised in the loss resulting 

 from the analysis. 



