The Geos 1 ion composition experiments has surveyed the plasma composition in the energy per charge range below 16 keV/e at all local times and at L=3--8. During quiet and moderately distrubed times, H+ is the dominant species with a few percent of heavy (M/Q>1) ions. Substorms and storms increase the relative amount of heavy ions, and occasionally, they can become the dominant species in the outer magnetosphere. Two sources, the solar wind (characterized by 4He++) and the ionosphere (characterized by O+), give on the average comparable contributions to storm time plasma, although in individual storms one or the other may dominate. Data presented here suggest that high-altitude thermal plasma or the plasmasphere (characterized by He+ and O++) must be considered as a third source. Under storm conditions with Geos in the dawn-noon local time sector we have observed a mixed commposition region just inside the magnetopause where high fluxes of H+, He++, O+, and occasionally He+ ions are present. During several storms a composition profile could be measured down to L~3. Both O+ and He+ increase toward low altitudes, and O+ (within our energy range) can become dominant at the inner edge of the ring current. On April 30, 1978, during a storm, O+ contributed >8% to the total local energy density of the ring current particles at L=4.1. In no storm has He+ been observed to be the main constituent during the recovery phase. During storm recovery, H+ and O+ are the dominant ions, the H+/O+ ratio remaining constant or even increasing during the days following the main phase of the storms. This suggests that charge exchange is not the only loss mechanism for the storm time ring current and/or that H+ is replenished during the recovery phase.