 Eroded remnants of volcanic dykes occur including at Resolution Picnic Area at West Head and Campbells Crater near Cowan, which provide for forests of Sydney blue gum ("Eucalyptus saligna").The park's highest point is 246 m at Willunga Trig near West Head Road which runs along the ridge of the Lambert Peninsula.The first inhabitants of the area were the indigenous Guringai people, after whom the park is named.