Interestingly, I recently learnt that there are boomerangs in the ancient Egyptian museum, these were called "foreigners weapon" by the dynastic Egyptians, and some of their maps point to a land formation that could be Australia. Then there are the Gosford Glyphs carved into some rock formations in Australia, recently translated and dated to the Ptolemaic / pre-Ptolemaic period. The hieroglyphs tell a story of a shipwrecked Egyptian flotilla. Also, the "where is the metal" argument is easily discredited, and even archaeologist don't argue over this any more. Over history, any metal has typically been looted, melted down, and turned into weapons and armour. Far, far easier than mining and smelting.