The East Pacific Rise collided with western North America in the last 30 m.y. A model in which the preexisting transform geometry was preserved as the actively spreading ridge was subducted under the continent accounts for the gross features of tectonic geometry of the west coast including the mountain blocks and deep Neogene sediment basins of the Transverse Ranges. The present day geometry in this model has transform motion at the surface along the San Andreas Fault and parallel features with decoupling to the East along the old subduction interface.