One of the present-day major lithospheric plates, the N. American Plate extends from the Mid-Atlantic Ridge in the east to a complex pattern of subduction zones and transform faults which form its boundaries with the Pacific, Juan de Fuca, Gorda, Cocos, Caribbean, and South American Plates in the west and south. Along the western side, the N. American Cordillera has been interpreted as a collage of accreted allochthonous terranes.