Gradually, the completely different landmasses moved to their present places. Gradually, the igneous rock constructed up into small volcanic islands above the surface of the ocean. Over time, these islands grew greater, partly as the results of extra lava flows and partly from the buildup of material scraped off descending plates. When plates carrying islands subducted, the islands themselves did not descend into the mantle. Their material fused with that of islands on the neighboring plate.
