We interpret marine magnetic anomaly data from the southern part of the New Hebrides basin as slirnving that a fragment of Late Paleocene-Late Eocene oceanic crust is preserved between the New Caledonia-Loyalty Islands platform and the New Hebrides island arc-trench system. The magnetic lincalions which trend about NE-SW, are interpreted as anomalies 18 through 23 (42-55 my. B.P.) with the inferred crustal ages increasing to the north. Drilling at DSDP site 286, which is located on oceanic crus1 hlightly older !han 55 m.y. according to our magnetic anomaly identifications, revealed mid-Eocene sedinicnts overlying igneous basement.