Abstract Beaches are well sorted, usually laminated, deposits of sand, gravel, and shell formed in the littoral zone and the zone immediately to seaward by the action of waves and currents. They are usually long, thin, and narrow. They are most extensive on youthful to mature coastal plain shorelines and are most likely to be preserved and covered by other formations where the land is sinking. Characteristics that may be helpful in identifying ancient beaches are summarized and a few examples of such deposits are mentioned. Beach deposits do not make up a large part of all the sedimentary rocks but may be of great practical importance as reservoir rocks for oil and gas accumulation.