Measurements of the Energetic Particles and Ion Composition (EPIC) instrument on the Geotail satellite are used to investigate at high-time resolution the relative intensity enhancement of different ion species at energies ~10 keV--3 MeV during encounters of magnetic field structures attributed to flux ropes or plasmoids in the distant tail. An examination of six events reveals the new result that the composition varies considerably within the interval of the encounter of each structure as well as among different encounters. There is no consistent trend for enhancement nor reduction of energetic ions from the ionospheric source relative to that from the solar wind source during intervals of flux ropes or plasmoids. A possible interpretation is that these plasma structures are connected to a particle source or sources actively modifying their compositional content while they are being ejected downstream beyond ~100 RE. ¿American Geophysical Union 1994