Unexpectedly large ozone mixing ratios measured on the August 1977 Global Atmospheric Measurements Experiment of Tropospheric Aerosols and Gases (Gametag) flight from San Francisco, Calif., to Hilo, Hawaii, are first shown to be of stratospheric origin, then the most probable mode of transport is determined. Isentropic trajectories are traced backward in time from the observations to the boundaries of the stratosphere, close to the northern section of the Asiatic continent. A travel time of only 3 days via the large-scale waves is almost 100 times faster than that computed from the zonal-seasonal mean circulations. Also, the laminar structure of the ozone distribution is consistent with a folded tropopause.