Hornsby Plateau
The Hornsby Plateau is a sandstone plateau lying to the north of Sydney Harbor, which is cut by steep valleys. The North Shore and the Berowra Valley National Park[1] are located on the Hornsby Plateau. Due to its hilly topography, it was slow to develop.[2] It has two main sedimentary rock layers: Hawkesbury sandstone, consisting mostly of sandstone, but with some shale, and the overlying Ashfield shale.