Grain-size and composition data for bottom grab samples are presented (at left). Samples generally consist of quartz-rich sand with subordinate amounts of gravel and mud. Locally, samples are rich in carbonate gravel or sand. Side-scan sonar low backscatter correlates with medium to fine siliciclastic sand with minor carbonate grains and is associated with the thicker sand-ridge deposits. The higher backscatter areas correlate with coarse grain size and increased carbonates. The coarse-grained sediments are usually <10 to 20 cm thick, occupy low areas adjacent to thicker sand bodies, and form ripples oriented N-S with a 40- to 70-cm spacing.
