The transgression of the basal Pennsylvanian across the older strata of the Ozark region involves a wide variety of problems, some of them more or less unusual in character, through as varied a range of subjects as physiography, paleogeography, stratigraphy, structure, and sedimentation. On some of these, considerable detailed information is already available, but most of it is widely scattered through the literature, whereas on others practically nothing has been written. For over twenty years, the writer has been living in the center of this interesting area, and has had almost constant contact with its problems, but not until recently has he realized that many of the conditions were more or less unique to the Ozark uplift. During the last three or four years, there has been a growing conviction that here is a field for important research on a great variety of phenomena of vital significance. It has . . .