The local and lenticular sands of many oil fields have undoubtedly originated as shore-line features (bars, hooks, and spits), in the seas of the geologic past.

An approximate genetic classification has been made of the more important types of these sand bodies, and the processes leading to their deposition and preservation in sedimentary strata have been considered in some detail.

From this study several conclusions have been drawn.

Offshore submarine bars are preserved as elongate, pod-shaped sand bodies of coarse material in offshore sediments. Their characteristics and stratigraphic relations are moderately favorable to oil accumulation.

Exceptional conditions of subsidence and sedimentation are necessary in order to bring about the preservation of barrier beaches within marine sediments. They would probably form straight, narrow deposits of coarse, well-sorted sand, exhibiting an almost lenticular cross-section, convex side upward. Their associated beds would be favorable to oil accumulation.

Many hooks, spits, bars, and tombolos, built out into deep water, hence below the depth of wave action, are preserved as marine sediments. Many local, lenticular oil sands probably originate as one or another of these forms. They are likely to vary greatly in shape and size, but in general their characteristics and stratigraphic relations fit them admirably to serve as oil reservoirs.