The geomorphology of depositional surfaces has been slow in developing. Adequate knowledge of deltas, deltaic plains, sand dunes, and eolian plains is very recent. Text books are still somewhat behind in adequate treatment of depositional geomorphology.

Adequate study of the subject requires topographic maps of finer detail than have commonly been available until recent years, and is much assisted by aerial photographs, soil maps, maps of vegetational distribution, and by studies of the materials of the geomorphic units mapped.

Recognition of regional patterns and topographic grain of depositional origins is an important part of the study. Foreign elements, such as diastrophic structures, may in some cases be mapped by interruptions and modifications of such patterns.

The systematic study of depositional surfaces adds much to the knowledge of geomorphology and late geologic history. It throws light also on climatology, soil science, archeology, and paleontology.