Complex sentence: Numerous islands lie within the Great Sound, most of them in the southeastern part of it, including Darrell's Island, Hawkins Island, Long Island, Marshall's Island, Hinson's Island and Watling Island.
Split into simpler sentences: Numerous islands lie within the Great Sound, most of them in the southeastern part of it. These include Darrell's Island, Hawkins Island, Long Island, Marshall's Island, Hinson's Island and Watling Island.