The contiguous hotel and resort belts of Batu Ferringhi and Tanjung Bungah and Tanjung Tokong along the northern beaches of Penang Island form the northwestern fringes of George Town. The central hills of Penang Island, including Penang Hill, serve as a giant green lung for George Town and an important forested catchment area. While the central hills have somewhat limited the westward urban sprawl, George Town's expansion is more evident southward along the eastern seaboard of Penang Island, creating the suburbs of Jelutong and Gelugor, the latter merging with the northward development of Bayan Lepas.