INTEREST has been increasing recently in submarine canyons because of the question of their origin and the part which they are thought to play in funnelling sediment from the continental shelf to the deep ocean1. Shepard and Dill2 have summarized the evidence concerning bottom currents observed in submarine canyons. Following the pioneer use of current meters by Stetson3 in some canyons on the Atlantic margin of North America, there have been some observations of current activity in these canyons made from submersibles4,5. The data on bottom currents presented here were obtained from near the head of Wilmington Canyon, which indents the outer margin of the continental shelf 140 km south-east of Delaware Bay (Fig. 1A).