The Formation and Movement of Sand Bars by Wave Action

Sand bars lying parallel to the coast are characteristic features of many sandy beaches and are found under widely different circumstances. They vary considerably in size and form, but all belong to one of two types; one type being found on non-tidal beaches and the other on beaches with a considerable tidal range. This latter type will be referred to as ridge and runnel beaches to avoid confusion with the former type, which will be called barred beaches.''