The Chattanooga shale, which is a widespread formation of small thickness and remarkably uniform character, is absent locally in Osage and Kay counties, Oklahoma, and the adjacent counties in southeastern Kansas. Microscopic studies of well cuttings made by oil-company geologists and the senior writer indicate that there is one large area and several small areas that contain no Chattanooga shale (Fig. 1). The Chattanooga shale in wells and on the outcrops in northeastern Oklahoma, 80 miles from the large shale-free area, is black carbonaceous fissile shale of uniform character. It contains a basal sandstone in some localities that is called "Misener sand" by the drillers. Gray shale, locally called "Kinderhook shale," overlies the Chattanooga black shale in parts of the r gion and is interbedded with the upper part of the black shale in some localities. The exact age relationship of the black and gray shales is not known. The data are insufficient to enable the writers to determine the method by which the Chattanooga shale-free areas were formed.