56 



det imellem 900 og 1100 Favne. I den Bugt af Havbunden. 

 der ligger Nord for Vesteraalen, optræder Biloculinleret 

 forst paa et Dyb af mere end 1200 Favne. Grændselinien 

 herfra og nordover indtil den 80de Breddegrad ligger imel- 

 lem 1000 og 1100 Favne. Paa det samme Dyb begynder 

 Biloculinleret i den sydligere 1 >el af Nordhavet, hvor dette 

 grunder op mod Færø — Islandsbanken. 



Jeg har tænkt mig. at den ovenstaaende Betragtning 

 af Biloculinlerets Udbredelse maaske senere kan blive en 

 Støtte ved det fremadskridende Studium af Expeditionens 

 fysiske og zoologiske Materiale. Tildels med det samme 

 Hensyn for Øiet. har jeg anlagt mine kemiske Undersøgel- 

 ser af dette Sediment, til hvilke jeg nu vil gaa over. 



Den kvalitative Undersøgelse af Biloculinleret viser, 

 at det foruden Jern. Lerjord, Kalk. Magnesia, Kiselsyre 

 og Spor af Fosforsyre indeholder smaa Mængder af Man- 

 ganoxyder. De sidste forekommer dog ikke som synlige 

 Bestanddele af Lermassen i Lighed med de smaa Korn 

 ell"i- Klumper, der saa ofte blev fundne ved Challenger- 

 expeditionen. men synes at maatte være meget fint fordelte 

 i Bundprøverne og udgjør i det Hele tåget en saa ringe 

 1 )el af deres Bestanddele. at de vanskeliggjør en kvantita- 

 tiv Bestemmelse. 1 )et .er muligt, at Manganoxyderne kan 

 bidrage til "at give Leret en stærkere brun Farve. Ved 

 Ophedning udvikler Biloculinleret en temmelig stærk empy- 

 reumatisk Lugt. 



For den kemiske Undersøgelse af Biloculinleret har 

 jeg forst og fremst udvalgt mig en Del Hovedstationer fra 

 forskjellige Punkter af Nordhavet og analyseret Bundprø- 

 verne fra disse fnldstændig med Hensyn til alle Bestanddele. 



I det følgende har jeg opstillet mine Analyser etter 

 Numeret af de Stationer, hvor Bundprøverne er optagne. 

 Bestemmelserne er udført efter den paa Side 36 beskrevne 

 Methode. 



Station 51. 



N. B. li."»" f).')'. V. L. 7° 18'. 1103 Favne 

 Meter). — 1.1". Lysbrunt Biloculinler. 



-J.Tl 

 1.14 

 2.7-1 

 ii.4'.i 

 0.93 

 52.82 

 Spor 

 9.37 



(2127 



boundary for Biloculina clay follows a depth ranging 

 from 700 to 800 fa thorns. < )ver the rapidly shelying bot- 

 tom off Lofoten and Vesteraalen. it extends between 900 

 and 1 100 fathoms. In the bight of the sea-bed north of 

 Vesteraalen the first Biloculina clay occurs at a depth of 

 more than 1200 fathoms. The boundary-line extending 

 from this locality northwards to the 80th pårallel of lati- 

 tude lies at a depth ranging from 1000 to 1100 fathoms. 

 This is the depth at which Biloculina clay first occurs in 

 the southern part of the North Atlantic, where its bed 

 shoals up towards the Færoe-Iceland bank. 



The above elucidative remarks on the distribution of 

 Biloculina clay. will, it is hoped, in some measure serve 

 to facilitate the progressive working out of the large 

 amount of physical and zoological material collected on the 

 Norwegian Expedition. Moreover, my chemical investiga- 

 tion of that deposit. to the results of which I shall now 

 pass on. has been moditied with the same object in view. 



A qualitative analysis shows that Biloculina clay. along 

 with iron. alumina, lime. magnesia, silica, and traces of 

 phosphoric acid. also contains small quautities of oxide ut' 

 manganese. The last of these constituents does not how- 

 ever occur in a visible tonn. as small granules or conere- 

 tions. so frequently met with on the "Ohallenger" Expedi- 

 tion. hut would appear to be most sparingly distributed 

 throughout the deposit. of which it constitutes so small a 

 proportion as hardly to admit of being quantitatively de- 

 termined. Possibly. this oxide of manganese gives a darker 

 colour to the deposit. On exposure to heat, Biloculina 

 clay. emits a pungent empyreumatic odour. 



For my chemical examination of Biloculina clay I 

 selected samples brought up at some of the principal ob- 

 serving-stations in different parts of the North Atlantic, 

 submitting portions of the deposit to a rigorous general 

 analysis embracing all its constituents. 



The analyses are arranged according to the numbers 

 of the Stations at which the samples of deposit were col- 

 lected. The method of determination was that described 

 on page 36. 



Sfatio)i 51. 



Lat. 65° 53' N, long. 7° 18' W.; 1163 fathoms 

 (2127 metres); bottom-temperature — 1.1". Light-brown 

 Biloculina clay. 



Decomposed 



by 



Kydrochloric acid 



73.40 per cent. 



Loss by ignition . 

 Protoxide of iron . 

 Sesquioxide of iron 

 Alumina . . . . 

 Magnesia . . . . 

 ( larbonate of lime . 

 Phosphoric acid 



2.71 

 1.14 

 2.7 4 

 6.4'.! 

 0.93 

 52.82 

 Traces 



Silica 9.37 



