Cheniers of Southwestern Louisiana

Abstract

SEVERAL long, narrow, sandy ridges run roughly parallel to the coast of southwestern Louisiana. Rising slightly above surrounding marshes, lakes, and watercourses, all essentially at sea level, these low ridges form the most conspicuous topographic features of the region. Sharply localized, well drained, and fertile, they support naturally a luxuriant vegetational cover in which large evergreen oaks form so striking a part that, quite deservedly, the ridges have been called cheniers' by their Creole inhabitants. Many of the cheniers have been cleared. Cotton fields cover large parts of the highest and most accessible; those lower and more distant form bases for grazing, trapping, hunting, and fishing. Where they are served by roads or navigable waters, the population is relatively dense and prosperous. It is not the purpose of this paper, however, to consider cheniers in their cultural aspects. We are here concerned with their origin, a history involving several of the dominant geologic processes affecting the Gulf Coast during Quaternary time. The entire Gulf Coast of the United States is a splendid exhibit of the consequences of active submergence. The mouth of practically every river is estuarine. From the Caloosahatchee, of southern Florida, to Baffins Bay, of southern Texas, the coast is marked by a dozen or more large bays and a much larger number of less conspicuous drowned river mouths. The subsidence causing this condition is so rapid that in the entire distance only two rivers, the Mississippi and the Appalachicola, have been able to build deltas protruding into the Gulf. The Mississippi has done so because of its enormous size and load, the Appalachicola because it drains an anticlinal region undergoing active uplift. The absence of deltas along the Gulf Coast might not be particularly significant were the streams clear and their burdens small, but the opposite is the case. Any comparatively short period of crustal stability would witness not only the rapid filling of their estuarine mouths but the growth of deltas into the Gulf as well.2 The effects of submergence extend well inland. Practically every stream immediately inland from the coastal marsh zone flows down