The surfacial bottom sediments on the nearshore to infer continental shelf off the Taean Peninsular, west coast of Korea are dominantly medium-grained clastic sands. About 60% and 20% of these clastic sands are partly iron-stained quartz and completely iron-stained quartz, respectively. Characteristically glauconite grains are abundantly found in these clastic sands. The mineral compositions of clastic sandy sediments in the study area are very similar to those of East China continental shelf sediments. Accordingly, such iron-stained quartz grains, glauconite grains and associated textural characteristics seem to indicate that those sandy sediments are relict sediments related to past condition, i.e. Quaternary low stands of sea level.