The altitude distribution of O(3P) above White Sands, New Mexico (33¿N), was investigated in situ at 1900 hours MST (0200 UT) on December 2, 1975. A rocket-borne OI 1304-¿ resonance-scattering system provided data over the altitude range 75--126 km on ascent and descent. The oxygen profiles inferred from the data exhibit considerable structure, with more structure evident on ascent than descent. A double peak (?1011 cm-3 at 90 and 98 km) occurs in both profiles. Ground-based photometric measurements of the [OI> 5577-¿ airglow at the time of the flight agree with the [O> measurements to within 50% when interpreted within the framework of either the Chapman or Barth mechanisms. Preliminary consideration of several processes leads to the suggestion that wind shears provide the best possibility for explaining the double-peaked concentration profiles.