The Tertiary sediments of the Gulf Coast offer the world's finest available laboratory for a broad study of sedimentation. The deep drilling of the past few years furnishes accurate logs and samples to a depth of about two miles over a large area of relatively undisturbed sediments. The Gulf of Mexico with its shorelines parallel to the strike of the sediments offers a present example of processes and distribution which may be compared to the past.

The bottom sample descriptions from Coast and Geodetic Survey charts have been compiled on a map of the Gulf of Mexico. The shape of the Gulf bottom based upon soundings has been studied with respect to the action of currents and waves upon distribution of sediments. The following zones of deposition are outlined and discussed: continental, lagoonal, the sand zone, the mud zone, the coral zone, and the deep sea muds.

Four cross sections, exaggerated 20 times vertically, have been drawn from the Cretaceous outcrop across the Gulf. The profiles of the Gulf which accompany the subsurface section relate the present sedimentary zones to those of the past. The detail of the subsurface sections shows a comparison of the various sand groups as to distribution, volume, extent, and probable effects of deltas, currents, and waves. Compared to one another, the sections show the type and relative amount of deposition on different parts of the Gulf Coast and place the time and location of the outstanding depositional events.

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