Convergent and upwelling circulation within the shelfbreak front in the Middle Atlantic Bight are detected using a dye tracer injected into the bottom boundary layer at the foot of the front. From the three day displacement and dispersion of two dye injections within the front we infer Lagrangian isopycnal (diapycnal) velocities and diffusivities of 2¿10-2 m/s (4¿10-6 m/s) and 9 m2/s (6¿10-6 m2/s). These results substantiate model predictions of Chapman and Lentz [1994> and previous dye tracer observations by Houghton [1997>. ¿ 1998 American Geophysical Union