Experiments are performed examining particle settling from constant-flux surface gravity currents and from a near stationary layer of particle-bearing fluid overlying a saline ambient fluid. The particles consisted either of clay or of near-spherical glass ballotini with four different mean diameters. In the case of ballotini with relatively large diameters (>~ 46 microns), the particles formed a settling front within the current consistent with their predicted settling velocity. A single particle plume descended below the current over the extent of the settling front. In the case of clay and tiny ballotini with diameter 6 microns, no settling within or below the current was observed before the current nose reached the end of the tank and the source was turned off. After a time on the order of minutes, these particles were found to descend from the near stationary surface layer through convective instability, though this may have been preconditioned by a fingering instability in the stratified interface between the upper and lower layers. Even though the particle concentration in the current and upper layer was less than 0.5% in all experiments, the front of the particle plumes descended at significantly greater speeds than the settling velocity of an individual particle. The relative descent speed was larger for smaller particles being on the order of 1000 times larger for clay particles.