There is, of course, much that is common, in regard to their Decorative Art, to all the tribes of Central and Northern Australia, especially in respect of the ornamentation of their commoner weapons and implements, so that much of what we have already written on this subject holds true of the tribes now dealt with. On the other hand, there are certain forms of design restricted to special parts of the country and characteristic of different tribes or group of tribes. In the west of the continent we have the incised and painted zig-zag pattern; in the centre there is the strong development of spiral and concentric circles drawn on the ground, rocks, and sacred objects. So again, in the far north, we meet with quite a different scheme of design, the most characteristic being that of the Melville and Bathurst Islanders, whose drawings and decorations are entirely distinct from any on the mainland and suggest contact, in past time, with a people whose art was more akin to that of the islands to the north-east than it is to anything in Australia. Then again, amongst the Kakadu nation, we meet with rock and bark drawings superior to any amongst the central tribes.