Between 5-20 paleocurrent directions have been measured from ripple marks in subhorizontal sandstone beds in each of 39 localities in Atokan and Des Moinesian rocks in the Arkoma Basin in E.-central Oklahoma. Several working hypotheses can be framed and significance tests can be applied to prove whether these hypotheses are true within a probability of 95%. The following conclusions were reached: 1) Measurements from adjacent beds in a locality are stochastically independent. 2) The deviations of the individual values are approximately normal in distribution around their arithmetic mean. Nearly all measurement samples are taken from normal populations with the same variance. 3) The over-all average current direction remained constant during Lower Pennsylvanian time in the entire sample area. 4) This over-all average current direction was southward and at right angles to the Arkoma Basin flexure. The course of the latter is assumed to be subparallel to the structure contours on the base of the Atoka Formation. Thus, currents flowed southward from the Ozark uplift into the Arkoma Basin.