In order to clarify the present confusion in the names, correlation, and mapping of the Quaternary surface formations of the Gulf Coast region of the United States a modified stratigraphic classification based on the section in coastal southwest Louisiana is proposed. It consists of the following formations: Citronelle, Lissie, Oberlin, Eunice, Holloway Prairie, and Recent.

Corrected correlations and mapping for the various parts of the region are given. Origin of the formations and correlations with Quaternary sections of the Atlantic Coast and Northern Interior regions are discussed.

The Citronelle is correlated with the Willis formation of Texas. The former Beaumont formation is divided into Oberlin (lower Beaumont) and Eunice (upper Beaumont). The Holloway Prairie is recognized as a Pleistocene terrace in many of the coastal river valleys. A late Wiconsin element, the Sicily Island, is recognized in the Recent of the Mississippi River Valley.

The current use of the names of the Pleistocene terraces of Red River Valley, Louisiana, for formations outside of that terrace area is shown to be incorrect because of miscorrelation with the coastal section. The correct correlation of the terraces is given as follows: Williana = Lissie, Bentley = Oberlin, Montgomery = Eunice, and Prairie = Holloway Prairie.

Suggested correlations of the Gulf Coast Quaternary section with that of the Atlantic Coast region are: Lissie = Okefenokee, Oberlin = Wicomico, Eunice = Pamlico, Holloway Prairie = Silver Bluff. Correlations with the Quaternary of the glaciated areas of the Northern Interior are: Citronelle = pre-glacial, Lissie = Aftonian, Oberlin = Yarmouth, Eunice = Sangamon, Holloway Prairie = Mid-Wisconsin Bradyan, Recent = post-Mankato.

Quaternary history is interpreted as having been initiated on the North American continent by uplift and warping of interior areas on such a scale as to have caused a sharp rejuvenation of the forces of erosion and transportation and to have resulted in the deposition of the coarse Citronelle as a basal formation along the Gulf Coast. Decreasing coarseness of latter deposits is interpreted as indicating the subsequent continuous gradual degradation of the interior areas. The series of glacial invasions of the Quaternary is interpreted as having begun after the deposition of the Citronelle, and as probably not yet concluded.