Complex sentence: Hakluyt Island lies off the western shore of Northumberland Island and is part of a small group of costal islands formed by Northumberland Island, Herbert Island and Hakluyt Island, being the smallest of the group.
Split into simpler sentences: Hakluyt Island lies off the western shore of Northumberland Island. It is part of a small group of costal islands formed by Northumberland Island, Herbert Island and Hakluyt Island, Hakluyt being the smallest of the group.