In a centrally condensed solar nebula, the gas is partially supported by a pressure gradient, and rotates at less than the Keplerian velocity. Solid bodies lack this support, and spiral inward due to drag. The radial velocities developed can be significant, even in low-mass nebular models. Possible effects include fractionation of particles by size or density, rapid accumulation of planetesimals, and production of regions of anomalous (non-solar) composition in the nebula.