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A study of 22 cores confirms that certain bulk and textural properties of deep‐sea sediments have a definite bearing on the transmission speed of sound through marine deposits. The higher the porosity, moisture content, and void ratio, the lower is the sound velocity. Increases in wet density are matched by increases in transmission speeds. There is no apparent correlation between sound velocity and either dry density or carbonate content. Shear strength is not a reliable index of transmission speed. Sound velocity is strongly related to grain size. Turbidites have high velocities, ash layers have intermediate velocities, and deep‐sea muds and clays have low velocities. There is a relation between transmission speed and sorting, skewness, and transformed kurtosis, but these size measures are dependent upon mean grain size. Grain size governs the bulk and textural properties of unconsolidated marine sediments and is the most important physical property in determining the acoustical nature of deep‐sea cores.

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A survey of 250 long piston cores from the North Pacific Ocean reveals that cores taken within definite areas of the sea floor have common sediment characteristics. These belong to distinct regions and are named sedimentary provinces. Three orders of sedimentary provinces occur in the North Pacific Basin. First order provinces follow the general form of the basin and are of great areal extent. They are sites of pelagic deposition and are named the Central North Pacific, Japan-Kuril, and Aleutian-Alaskan Provinces. Because the North Pacific Basin is protected from large-scale basinward transfer of terrigenous sediment, the limits of first order provinces match the boundaries of major water masses. Second order provinces are dominated by features of positive submarine relief, are restricted in size, and their boundaries follow the configuration of hills and ridges. They include the Hawaiian Ridge, Marcus-Necker Ridge, Shatsky Rise, Emperor Seamount Chain, and Ridge and Trough Provinces. Sediment accumulating on and around these features is a function of the depth of crestal portions of submarine highs. Third order provinces constitute a narrow zone of terrigenous sediment around the rim of the North Pacific Basin. Included are the floors of the circum-Pacific trench system and a portion of the northeastern corner of the Pacific. Two are named: the Aleutian Trench and the Northeast Pacific Turbidite Provinces.

The northeast corner of the Pacific Ocean is a region of turbidity‐current activity. Cores from this area are dominated by very fine‐grained sand and medium‐grained silt that grade upward to clay. The results presented in this article are based on 217 textural analyses of turbidite layers comprising 30 piston cores. It is possible to distinguish proximal and distal facies of turbidites using characteristics of layering, grading and texture. Features of the proximal facies include wide range of layer thickness, maximum layer thickness, non‐grading, truncation of grading, textural reversals, and sand at the base of graded layers. Areas beyond main routes of submarine flows are sites of episodic addition of silt‐through clay‐sized sediment. The proportion, thickness, and mean grain size of the silt decreases with increasing distance from the main avenues of flow.