The Newfoundland/Flemish Basin and its conjugate passive margin, the northwestern Iberian Peninsula, were con tiguous in the late Early Cretaceous. Therefore, we infer that these margins were subject to similar tectonic and sedi mentary processes during their early evolution. A comparison of these conjugates using multichannel seismic-reflection (MCS) profiles shows similar acoustic basement in the Newfoundland/Flemish Basin underlying the J anomaly (M0-Ml) and beneath the Iberian Abyssal Plain at a peridotite ridge interpreted as a mantle diapir. ODP Leg 103 sampled the peridotite ridge at Site 637, and although the crust at Site 637 exhibits no anomalous magnetic signature, it is collinear with the J anomaly trend southeast of the Grand Banks of Canada in a previous pre-drift reconstruction.Both margins exhibit a high-amplitude, rhythmically layered "rift" sequence bounded at the top by a prominent, high-amplitude sequence boundary interpreted to be a break-up unconformity of late Early Cretaceous age. The early "drift" sequences on both margins consist of lower amplitude, discontinuous reflections to which we assign an early Al bian to Cenomanian age. Results of these comparisons support developing correlations between Grand Banks stratigra phy and the deep Newfoundland/Flemish Basin, and are consistent with our current interpretation of the nature of the Newfoundland/Flemish Basin crust and the position of the ocean/continent boundary off this part of eastern Canada.