Beach is the general term for amassed area on seashore with unconsolidated sediments (sand, gravels, soil etc).  The beach is located at the tidal zone/belt—between the high tide line and low tide line, usually lies as a cover of temporary sediments on billows tableland or gathers at the edge and bottom of the tableland and sea.  The size and the ebb and flow of beach change with the seasons.  If the sediments of the beach mostly contain tiny sand, it is a sandy beach.  Xi-yu township is an island of squarely hill, and its sandy beaches mostly amass inside the bay and on flatter area of the tidal zone where the size of the sandy beaches are smaller.

In broad sense, beach refers to the amassed area of the seashore while in a narrow sense it refers to the amassed area of the tidal zone.  If the sediments of the beach are loose sand granule (with diameter 2-1/16 centimeters, it is named as sandy beach.  And if the diameter is more than 2cm, it is then named as gravel beach.  Sandy beach is mainly consists of trifles of corals, shells of Kong worms and small amounts of quartz sand, shattered basalt and soil.  The color of the sandy beach has something to do with the materials on the beach surface: if the beach mainly consists of quartz sand and corals, the beach surface will appear as whitish-yellow.  Most of the sandy beaches on Xi-yu township are shattered corals sandy beach.