Shoreline can be considered to include the entire sedimentary regime encompassing the actively forming subaerial shore features, as well as the seaward extent of wave conditions capable of causing significant bottom disturbance. This offshore area corresponds to Dietz's "active surf lens," the seaward boundary of which commonly is at a 10-meter depth. The relatively narrow strip of the continent known as the shoreline is an area of extremely complex and variable sedimentation with highly variable morphology and sediment types. The importance attached to the understanding of shoreline processes by geologists is indicated by the large volume of literature concerned with this subject. In addition to being of interest to petroleum geologists because of the role of ancient sho elines as traps and reservoir rocks, the study of nearshore processes has immediate application toward solving the ever-growing shoreline engineering problems now being found along populated coasts.

The forces involved in shoreline processes are both subaerial and subaqueous and include wind, waves, tides, and chemical and biological agents. Important recent approaches to the study of these forces have been the quantitative works of Bagnold and Inman and the fluorescent grain-movement studies by Ingle and others.

Emphasis of the discussion of shoreline processes is on the Atlantic Coast of the United States between Cape Hatteras and Miami. Among other interesting aspects of this area is the particularly sharply defined "active surf lens," characterized by relatively fine grain size, in a "band"--usually less than 12 miles wide. Little sand-size material presently is being contributed by rivers and evidence is presented indicating that most shoreline sediment here, including beach and estuarine sand, is derived through winnowing and shoreward transport of central and outer-shelf material. The effect of varying wind and wave energies, tidal amplitudes, longshore current activities, and other factors is also exhibited along the southern Atlantic Coast of the United States.

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