Starting from a position below the paleoequator in the the ancient Pacific Ocean in the Carboniferous, the terrane Wrangellia drifted northward a distance of about 10,000 km and eventually collided with western Laurentia in the Cretaceous. Wrangellia is the only terrane shown on these sketch maps. The ancient Pacific was crowded by other isolated terranes. Some of these terranes eventually collided with Laurentia to form parts of the Cordillera, others formed parts of eastern Asia. The maps also depict the break-up of the supercontinent Pangaea (Ma = million years).
