Complex sentence: It is studded at its southern end with a chain of shoal reefs that are collectively called Adam's Bridge, Pamban Bridge (India), and Mannar Island (Sri Lanka) is found at its southern end.
Split into simpler sentences: It is studded at its southern end with a chain of shoal reefs that are collectively called Adam's Bridge. Pamban Island (India) and Mannar Island (Sri Lanka) are also found at its southern end.