Three shipboard experiments are described that verify the importance of bottom intrusions of Gulf Stream Water in exchange processes on the continental shelf of Cape Hatteras. Preliminary evidence indicates that onshore flow of Gulf Stream Water at the bottom is compensated by offshore flow of Shelf Water at the surface. A schematic model of the exchange process during stratified summer conditions indicates that vertical mixing between Shelf Water and Gulf Stream Water accross weakened portions of the pycnocline can account for the cool dense lens of bottom water often observed in the mid-shelf region south of Cape Hatteras.