The need for a more thorough understanding of sedimentary principles has become increasingly apparent as geological exploration for petroleum moves toward the location of nonstructural traps. The present paper reviews some of the principles involved in the study of sedimentary environments, and attempts to show that a study of fundamental properties of sediments may prove basic to future exploratory work.The role of basic research is to explore new paths to knowledge through the evaluation of such fundamental sedimentary parameters as size, shape, roundness, composition, surface texture, and fabric. The relation of these parameters to mass properties such as porosity and permeability needs study, and a knowledge must be gained of conditions that control the lateral and vertical variations of these mass properties in sedimentary environments. From such fundamental studies, indices that are helpful in tracing porosity wedges and flank sands may be developed. In addition to studies of clastic sediments, conditions of formation of non-elastics must be attacked. The role of practical application lies with petroleum geologists, whose task includes the use of the newer principles in exploration, and their further development or discard as exploration continues.It is emphasized that sedimentary research is only one of several lines of attack on petroleum exploration by geological methods. The closer coordination of paleontologic, stratigraphic, and sedimentary work should insure a continuously expanding frontier in the geological search for oil.