sentences:  Magnetic lineations as old as M29 are not known from other oceans, and the area in the Western Pacific that lies inside the M29 lineation – that is, crust older than M29 – is on the order of 3x106 km2, about a third of the size of the United States.ODP site 801 lies on seafloor that isconsiderably older than M29 and the MORB basement there yields Ar-Ar ages of 167±5 Ma .The oldest sediments at site 801C are middle Jurassic, Callovian or latest Bathonian (~162 Ma; ).