246 PETROLEUM GEOLOGY/Overview Figure 20 Orthocontours reconstructed subsalt petroleum migration pathways, Ewing Bank to Green Canyon areas, Gulf of Mexico, USA Reproduced with permission from McBride BC, Weimer P, and Rowan MG (1998) The effect of allochthonous salt on the petroleum systems of the Northern Green Canyon and Ewing Bank (Offshore Louisiana), Northern Gulf of Mexico American Association of Petroleum Geologists Bulletin 82: 1083 1112