Brisbane Water National Park: Sydney is surrounded by beautiful National Parks. Sixty kilometres north of Sydney and 9 kilometres south west of Gosford is Brisbane Water National Park with an area of 11,500 hectares. Hawkesbury sandstone is the principal rock type of the Park. This sedimentary rock is noted for its low fertility, good drainage and the ability to support a diverse and bewildering range of native plants. In spring the Park becomes alive with the flowers of Banksias, Grevilleas, Hakeas and particularly Waratahs. The Waratah is the floral emblem of NSW and Brisbane Waters National Park protects a large population of this beautiful shrub. The park is also home to a number of Aboriginal engraving sites.Walking tracks traverse the Park and there are lookouts and picnic areas at various sites. Warrah Trig, on the Woy Woy-Patonga Road is a lookout, which gives splendid views across Broken Bay. There are picnic areas at Girrakool and Somersby Falls (pictured).