Fossil sites containing the remains of animals now extinct on the Australian mainland have been discovered in northern Queensland, paleontologists say. Researchers from the University of Queensland say the cluster of locations are a \"fossil goldmine\" that will help them study the dramatic change from Australia\'s ancient rainforest to today\'s arid landscape, The Australian reported Wednesday. \"There\'s a diversity of (extinct) possums, a bunch of bandicoots, white-footed tree rats and numerous frog species,\" paleontologist Gilbert Price said. \"There are bigger species, megafauna, including several species of kangaroo, Macropus.\" Price estimated the oldest fossil deposits discovered in three limestone caves date to from 400,000 to 500,000 years ago. They add to similar finds at a 250,000-year-old site near Rockhampton, north of the state capital of Brisbane, discovered in 2007. Studies have suggested extreme climate change drove the extinction of the rainforest and its animals from 205,000 to 280,000 years ago, following a long period of relative stability spanning several glacial cycles, researchers said. \"This more northerly deposit allows us to track that exciting period,\" Price said.