The Deposits of the Sea- Bottom. 



By 



O. B. Boggild. 



Of all the branches of geological science scarcely any has hitherto been subjected to so little 

 systematic treatment as the science of the deposits of the sea-bottom. Most of the literature 

 treating of this subject, consists of more or less dispersed observations; most frequently the work 

 has been confined to a description of the new animals found on the sea-bottom, and the deposits proper 

 have been subjected to no thorough petrographic and mineralogical examination. This branch of the 

 science, moreover, has had only little material for examination; for although in earlier times a sufficient 

 number of specimens from more shallow water near the coast have been examined, it is only lately 

 that specimens of the deposits in the deeper parts of the sea have been brought up in so great a 

 number, that it has been possible to form a clearer notion of their nature. Another impediment for 

 the systematic examination of these deposits has been the tinge of mysticism by which they have been 

 surrounded; much working-power has been wasted in theoretic speculations on the many new and 

 remarkable phenomena shown by the deep-sea deposits, and for those speculations the treatment of 

 the less conspicuous, more general ingredients of the specimens, from which may be drawn inferences 

 of greater value to geology, has partly been slighted. Of late, however, considerable changes have 

 taken place in this respect; the material of several of the larger deep-sea expeditions has been in 

 many respects completely and exhaustively examined, while by other expeditions only small attention 

 has been paid to the deep-sea deposits. Two works, above all, have been of excellent use by my 

 examinations: the report of the Norwegian North-Atlantic expedition, part IX, Chemistry, by Ludvig 

 Schmelck, which report has in particular yielded material for comparison, as it gives a thorough 

 treatment of a locality, immediately bordering on that of the present expedition; and next the report 

 of the deep-sea deposits of the Challenger expedition, by F. Renard and John Murray, which 

 latter work gives a quite overwhelming mass of material from the whole earth, which material, how- 

 ever, cannot easily be used, as it has only partly been worked into more general results, what would 

 also require a task almost more than human. 



As the subject of my examinations I have had a collection of 91 tub-specimens, taken during 

 the two voyages of the Ingolf-expedition in the summers of 1895 and 1896. These specimens have 

 the great advantage that the}- are most frequently quite unaltered during the hauling-up, so that we 

 get an exact notion of the ratio between the different constituents of the specimen. On the other 

 hand, this kind of specimens has the drawback, that larger stones cannot be taken in them; as a 



The Ingolf-Expedition. I. 3. I 



