After the stop/start progress down the Darling, John and Tim find the Murray a veritable speedway. Tim winds up the Bismarck to full throttle; the mighty tinnie's never been faster. They declare it's a joy being on a river with water in it. After four weeks, our unshaven adventurers head east of Albury to the Barmah Forest where the renowned red gums and wetlands are dying of thirst. John and Tim looked at cotton irrigation on the tributaries of the Darling, now down on the Murray they take a look at rice farming near Renmark. To John it seems an absurd pursuit in the world's driest continent. After 4,000kms, gliding down exhilarating sections on the lower reaches of the Murray, John and Tim make good time before beaching the Bismarck and camping on the NSW/South Australian border. At least they think they do. A peculiar quirk of mapping has them very confused about whether they're actually in NSW or South Australia. With the Bismarck motoring beside spectacular cliffs on the banks of the Murray, Tim, otherwise known as the 'Indiana of Stones', sees things in the rocks and the land that the average person misses. A rocky cliff that looks an obstacle to getting ashore proves a potential treasure trove. After digging away at one cliff face, Tim finds fossilised coral and an ancient shark tooth, proving that the floor of the ocean was once here. John, too, appears to be developing a growing passion as a 'fossil hunter'.