W.D. Campbell recorded and sketched about 250 Aboriginal rock art sites across Sydney across nine parishes (predominantly engraving sites). A number of the coastal and what are now inner-city sites have been lost to development and weathering, but many of the engravings are still in good condition.
Located along the popular Spit to Manly bushwalk, the Grotto Point Aboriginal Site included boomerangs, fish, sharks and a large kangaroo. The engravings are about 1,000 years old and have interpretative signage.