The Gulf Coast of Texas and Louisiana belongs to a world community of Tertiary provinces that have been extensively drilled for oil, and in which the sedimentary characteristics of the producing formations are similar to the characteristics of modern sediments in the same regions to-day. The Gulf Coast is, therefore, one of the geological gateways through which the needs of geology may be expressed in terms of multiple investigations of Recent sediments, and through which, in return, the results of those investigations can be interpreted in terms of the geology of older rocks. The wide spread of sedimentary environments, the slight degree of regional folding, and the extensive development of oil fields from the Rio Grande to the Mississippi River make the Gulf Coast excep ional in its class.

The biological and lithological aspects of sedimentary facies in the Gulf Coast are reviewed. The principal results of investigations of "fossil" foraminifera in the Recent bottom sediments of the Gulf of Mexico are described. The patterns of distribution of foraminifera may be helpful in outlining a frame of reference for further sedimentary investigations in the Recent. General methods of applying the results of investigations to older rocks are described.