Doran's line drawing of an Australian canoe that was built by bunching and tying the ends of a half-tube of bark was obviously based on this fine early 19th-century engraving, from Lesueur and Petit's Atlas to Peron's "Voyage of Discovery." (I've transcribed the name of the source verbatim from Johnstone's caption, but unfortunately, there is no bibliography or footnote citation for this source.) In the engraving, one can see thwarts, and ties (probably bark) running across the boat, from shear to shear just above the thwarts, , but no gunwale members, ribs, or other structure. The Aboriginal people paddling in the background provide scale, showing that this was a small two-man canoe indeed. They are paddling with single-handed paddles, and they have a small fire going amidships. In the background, a man is carrying a similar boat above his head. From the abundance of ducks and other waterfowl in the image, one can safely speculate that the canoes were used for waterfowling, egg collecting, or both.
My earlier blog included Doran's description of the bark rafts of Tasmania, which stated that they were extremely temporary craft, becoming waterlogged in about six hours. Here's an image, from the same source as the above image, by way of Johnstone.
As Johnstone notes, these are similar in design to bundled-reed floats that were used widely in many cultures around the world, the Peruvian caballito pictured just a couple posts ago being an example. But given their short working life, Johnstone seems justified in calling them among the most primitive of craft. I have no information on what material was used to bind them together, nor on the type of bark used in the bundles.
Again, the two paddlers in the background show that this is a very small tandem craft, and it doesn't look particularly stable either. They carry poles, but apparently no paddles, and a pair of poles appear in the foreground as well. As any modern canoe poler can attest, however, poles can serve entirely adequately to propel a boat in deep water, as their projected area under water is often not much less than that of a paddle blade.