54 



Ved denne Expedition optoges nemlig fra Havbunden 

 en Mængde Klumper og Knoller, hvoraf enkelte ifølge Be- 

 skrivelsen maa være af en lignende Art som de ovennævnte 

 fra Station 40. Den betydelige Udfældning af Mangau- 

 oxyder. der ved samme Anledning blev paavist i Havbun- 

 dens Afleiringer, synes derimod ikke at have noget Side- 

 stykke i det europeiske Nordhav. 



.Jeg har forud omtalt, at det brune Ler kun synes 

 at udgjore et tyndt Lag paa Havbunden. Hvor denne 

 begynder at skraane op mod Kystbankerne og nærme sig 

 til det graa Lers Territorium, tinder vi i Særdeleshed ofte 

 i Bundprøven et underliggende Lag af det sidstnævnte 

 Sediment. Nedover mod Dybet tiltager det brune Ler i 

 Mægtighed, og indenfor Biloculinlerets Omraade tinder vi 

 de Heste Bundprover helt igjennem ensartede. De enkelte 

 Steder, hvor der ogsaa. ber tindes tvende forskjellige Lag i 

 Bundprøven og den Mængde af graat Ler. der optoges 

 med Skraben eller Trawlen, viser at Biloculiuleret er af 

 en forskjellig, men i det Hele tåget ringe Tykkelse. Paa 

 den 1 >el af Havbunden. der ligger omkring Stationerne 213, 

 214 og 215 paa et Dyb af over 1700 Favne synes Bilo- 

 culiuleret i Særdeleshed at være meget tyndt udbredt. Paa 

 Stat. 21f> udgjorde det graa Ler den overveiende Del af 

 Bundprøven og paa Stat. 213 fandtes kun Spor af Bilocu- 

 linler. 1 )ette graa Underler er meget tint. ensartet og 

 plastisk, og bliver etter Tørring meget fast og sammeu- 

 hængende. Leret indeholder ingen Dyrelevninger og Kalk- 

 gehalten er kun ubetydelig. Under Mikroskopet viser det 

 yderst smaa krystallinske Partikler (Kvarts?), der forst 

 træder tydelig frem ved en Forstørrelse af "uto — 600 Gange. 



De Bundprover. der blot bestaar af Biloculinler. er 

 i Almindelighed helt igjennem ensartede med Hensyn til 

 Ddseende og Foraminiferernes Skaller saa jevnt fordelte i 

 Lermassen. at ethvert Stykke af denne omtrent viser den 

 samme Kalkgehalt. 



Paa enkelte Steder forekommer dog i selve Biloculin- 

 leret en Lagdannelse. der giver sig tilkjende derved, at 

 Bundprøvens øverste Del bestaar af et brunt, tint Ler uden 

 Kalkskaller. medens der under dette tindes et porøst Ler 

 med en Mængde Foraminiferer. Denne Lagdannelse er af 

 en lignende Art som den. man erholder ved at slemme 

 Biloculiuleret ud i Vand og derpaa lade det afsætte sig. 

 Ved denne ( Iperation synker alle Kalkskaller tilligemed 

 andre grovere Partikler tilbunds, medens man øverst faar 

 et fint kalkfattigt Ler. De1 synes rimeligt at antage, at 

 en lignende Bundfælding allerede kan foregaa i Havet og 

 bidrage til den ovenomtalte Lagdannelse, men i saa Fald 

 maa man tristes til at spørge, hvorfor den ikke altid fore- 

 kommer i Biloculinleret. 



\'i mangler for Øieblikket Forudsætninger til at kunne 

 besvare dette Spørgsmaal, thi hertil kræves Kundskab om 



On that British Expedition numerous nodules and 

 concretions wére brought up in divers localities from the 

 bed of the sea, some of which, to judge from the descrip- 

 tion. must have been similar in character to those that 

 came up on the Norwegian Expedition at Stat. 40. Mean- 

 vvhile. the very considerable proportion of oxide of man- 

 ganese determined as a constituent of the deposit in which 

 the nodules lay imbedded. does not appear to accom- 

 pany the occurrence of such concretions in the North 

 Atlantic. 



As previously stated. the brown clay would appear 

 to constitute a comparatively thin surface-layer. Where 

 the sea-bed. shelving up to the coastal banks, begins to 

 approach the province of the grev clay. samples of the bot- 

 tom have very frequently an under laver of that deposit. 

 Downward, in the direction of the deptbs, the brown clay 

 increases in vertical extent. and within the limits of Biloc- 

 ulina clay, most samples of the bottom are found to be 

 homogeneous throughout. From the few samples which 

 even here consisted of two different layers. together with 

 the large quantity of grev clay brought up in the .dredge 

 or trawl. Biloculina clay is however clearly shown to be a 

 deposit of trifling though variable extent in a vertical direc- 

 tion. Throughout the section of the sea-bed surrounding 

 Stations 213, 214. and 215, at a depth of more than 1700 

 fathoms. Biloculina clay would in particular appear to be 

 very thinly distributed. At Station 215, the sample con- 

 " sisted in greater part of grev clay. and in that brought up 

 at Station 213, traces only of Biloculina clay were observed. 

 This grey underlying clay is tine, homogeneous. and plastic- 

 and becomes on being dried exceedingly tirm and cohesive; 

 it contains no animal remains and the amount of carbonate 

 of lime is inconsiderable (1 — 2 per cent). With the aid 

 of the microscope. minute crystalline particles (possibly 

 quartz). may be detected. which do not become distinctly 

 visible till magnitied tive or six hundred times. 



Samples of the bottom consisting exclusively of Bilo- 

 culina clay, are as a rule uniform in appearance throughout. 

 and the foraminiferous shells so regularly distributed in 

 the deposit. that every part of it has well-nigh the same 

 proportion of lime. 



In certain localities. however. the surface-layer of 

 Biloculina clay was found to be exceptional in formation: 

 a tine brown clay without calcareous shells constituted the 

 upper part of the sample, whereas the under laver con- 

 sisted of a porous clay containing great numbers of Fora- 

 minifera. This formation is similar to that of the deposit 

 lett on washing Biloculina clay, during which operation the 

 Calcareous shells and other coarser particles sink to the 

 bottom, leaving a Hue clay. containing very little lime. as 

 the upper laver. Some such precipita.ting process may not 

 improbably be going on in the waters of the ocean and 

 thus contribute to the formation described above; hut if so. 

 the question naturally arises why the latter is not an in- 

 variahle characteristic of Biloculina clay. 



Kor the full investigation of this subject we are at 

 present in waut of the requisite data. assuming as it does 



