Image d'archive à partir de la page 194 de la profondeurs de l'océan. Les profondeurs de l'océan : un compte rendu général de la science moderne de l'océanographie fondée en grande partie sur la recherche scientifique de la vapeur norvégien Michael Sars dans l'Atlantique Nord depthsofoceangen00murr Année : 1912 IV DES PROFONDEURS ET DES DÉPÔTS DE L'OCÉAN 159 associé à la glauconite dans certaines localités, plus particulièrement phosphatés au large du Cap de Bonne Espérance et de la côte Atlantique '°'''ti°'- de la United States, concrétions irrégulières, en grande partie composé de phosphate de chaux, ont été dragués. Les concrétions varient considérablement en taille

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Archive image from page 194 of The depths of the ocean. The depths of the ocean : a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic depthsofoceangen00murr Year: 1912 IV DEPTHS AND DEPOSITS OF THE OCEAN 159 Associated with the glauconite in certain localities, more Phosphatic especially off the Cape of Good Hope and off the Atlantic coast '°'''ti°'- of the United States, irregular concretions, largely made up of phosphate of lime, have been dredged. The concretions vary greatly in size and form, with a greenish or brownish glazed external surface, and are made up of heterogeneous fragments derived from the deposit containing the concretions (grains of glauconite and other minerals or remains of organisms), cemented by phosphatic material, which consti- tutes the principal part of the concre- tions. When the cemented particles are purely mineral, the phosphatic matter acts simply as a cement, but when the remains of calcareous organ- isms are included in the concretions, the phosphatic material plays a more important part, filling the internal chambers, and often the calcium car- bonate of the shell is pseudomor- phosed into calcium phosphate. When the filling up of a foraminifer, for example, and the pseudomorphism of its shell, are complete, the phosphate, attracted around this little centre con- tinues to be added at the surface, and thus a phosphatic granule is formed, the external appearance of which no longer recalls that of the organism around which the phosphate has grouped itself. These phosphatic con- cretions occur chiefly along coasts bathed by waters subject at times to great and rapid changes of tempera- ture, which cause the destruction on a large scale of marine life, the decomposition of the organic remains, sometimes thickly covering the sea-floor in such locali- ties, giving rise to the phosphate of lime to be permanently fixed in the phos

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