Results from a series of six ozonesonde balloon flights taken every 4 hours at a single station during a period when there was a strong confluence of polar air and subtropical air over the station are presented. The soundings in this case are found to be characterized by several highly persistent maxima and minima in the vertical distribution of the partial pressure of ozone in the lower stratosphere. The altitudes above the station at which these maxima and minima occur increase systematically from the beginning to the end of the series. This indicates that the maxima and minima correspond to thin sloping layers of ozone-rich air and ozone-poor air, respectively, that undergo a displacement with time along with the displacement of the pressure system with which they are associated.