The sediments which outcrop on land adjacent to the Gulf of Mexico are of Cretaceous and Tertiary age. They are neither strongly faulted nor folded except where the Rocky Mountains approach the coast in Mexico and at the mouth of the Gulf on the island of Cuba.

In addition there are known from wells sediments, principally of early Mesozoic age, whose time equivalents outcrop far inland. These sediments also are not strongly folded nor faulted.

Despite this evidence of stability on land, there is irregularity in topography wherever the bottom of the Gulf of Mexico has been mapped. On the continental slope, even on the continental shelf and just inside the shore line, evidence of recent movements has been mapped.

In this paper, geological and geophysical data are reviewed as to their significance in the light of Umbgrove’s formulation that “the phenomena of the continental margin are correlated with other periodic events occurring in the earth’s crust and its substratum”.