The Seowipo Formation on Jeju Island has different layers that show how they were formed. Some layers were made in the shallow water near the shore, while others were formed in deeper water. The researchers found different types of sandstone and mudstone in these layers, along with fossils of animals that lived long ago. They also discovered traces of storms that affected the environment where these rocks were formed. Overall, the Seowipo Formation gives us clues about the ancient environments on Jeju Island and how they changed over time.