Grain-size and composition data for bottom grab samples are presented below the sonar
imagery. Samples generally consist of quartz-rich sand with subordinate amounts of
gravel and mud. Many samples are rich in carbonate gravel or sand. Low backscatter
correlates with medium to fine siliciclastic sand with few carbonate grains. The higher
backscatter areas correlate with coarse gain size and increased carbonate. The
coarse-grained facies is thin and typically exhibits ripple crests which trend N-S
with a 40- to 70-cm spacing.