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Sea-Floor Texture and Physiographic Zones of the Inner Continental Shelf From Salisbury to Nahant, Massachusetts, Including the Merrimack Embayment and Western Massachusetts Bay

Figure 13. Inner continental shelf sediment textures within western Massachusetts Bay with bottom photographs A–D showing sediment texture as it is defined in select locations. Grain-size statistics are plotted as pie charts showing the relative percentages of gravel, sand, and mud. A, A photograph of the sea floor within an area classified as rock (R). No sample was recovered in this area because of large particle size. B, A photograph of a section of sea floor classified as primarily mud with sand (Ms). C, A photograph from a section of sea floor classified as primarily gravel with rock (Gr). No sample was recovered in this area because of large particle size. D, A photograph from a section of the sea floor classified as primarily sand and gravel (Sg) with some mud. This photograph is located near the boundary of a Sg and Gs texture transition. The viewing frame for photographs A–D is approximately 50 centimeters, and the locations of the photographs are shown as white dots on the sediment texture map. The location of the seismic-reflection profile from figure 18 is indicated by the black line. Sediment classes are shown in figure 8. %, percent.