The relations for the surface layers of sediments are discussed first. The CaCO₃ content depends upon the distribution of organisms, the admixture of terrigenous detritus, and the solution of calcareous particles of organic origin. Chemical precipitation of lime does not take place in the sea. The organic content of the sediments and the content of siliceous organisms are discussed. In the red clay, organic substances are deposited that are relatively resistant to decomposition compared with those laid down in blue mud, which is deposited more rapidly.

The mineral constituents vary considerably both in the microscopic fractions and in the finest fractions analyzed by X-rays. Relatively few minerals are formed anew in the sediment. The content of TiO₂, Fe₂O₃, MnO, P₂O₅, and As in numerous samples is discussed and the relation of K₂O to Na₂O is considered for a number of samples. The size distribution of the sediments is simple in only the two extreme types, blue mud and red clay on the one hand and Globigerina sand on the other hand. The increase of foraminiferal shells causes an increase of the coarse fractions.

The subsurface parts of the samples give an indication of the rate of deposition of the sediments on the basis of stratigraphic investigations of the Foraminifera. The rate is the greatest near the coast and on the Atlantic Ridge and is of the order of magnitude of 1 to 2 centimeters per 1,000 years. The calcium carbonate content in most places is less in the glacial sediments than now. The content of siliceous organisms shows no consistent relationship to depth. The organic content in general decreases with depth. The studies of the mineral content indicate no essential difference for the deeper parts of the cores and no particular diagenetic alterations. The extent to which differences with depth for the iron and manganese content are due to diagenetic changes or to differences in c nditions of deposition is uncertain. No diagenetic alteration of the clays is indicated by the size distribution, though in calcareous sediments the size of particles decreases, owing to disintegration of shells with depth.