A second area of the continent to contain a significant rock art tradition was that of Alpine Europe, with the majority of artworks being clustered in the southern slopes of the mountainous region, in what is now south-eastern France and northern Italy. Cave paintings are found in all parts of Southern Africa that have rock overhangs with smooth surfaces. Among these sites are the cave sandstone of Natal, Orange Free State and North-Eastern Cape, the granite and Waterberg sandstone of the Northern Transvaal, and the Table Mountain sandstone of the Southern and Western Cape. The oldest reliably dated rock art in the Americas is known as the "Horny Little Man." It is petroglyph depicting a stick figure with an oversized phallus and carved in Lapa do Santo, a cave in central-eastern Brazil. The most important site is Serra da Capivara National Park at Piauí state. It is a UNESCO world heritage site with the largest collection in the American continent and one of the most studied. Rock paintings or pictographs are located in many areas across Canada. There are over 400 sites attributed to the Ojibway from northern Saskatchewan to the Ottawa River. Australian Indigenous art represents the oldest unbroken tradition of art in the world. There are more than 100,000 recorded rock art sites in Australia. The oldest firmly dated rock-art painting in Australia is a charcoal drawing on a rock fragment found during the excavation of the Nawarla Gabarnmang rock shelter in south western Arnhem Land in the Northern Territory. Dated at 28,000 years, it is one of the oldest known pieces of rock art on Earth with a confirmed date. Nawarla Gabarnmang is considered to have one of the most extensive collections of rock art in the world and predates both Lascaux and Chauvet cave art - the earliest known art in Europe - by at least 10,000 years. In 2008 rock art depicting what is thought to be a Thylacoleo was discovered on the north-western coast of the Kimberley. As the Thylacoleo is believed to have become extinct 45000–46000 years ago (Roberts et al. 2001) (Gillespie 2004), this suggests a similar age for the associated Bradshaw rock paintings. Archaeologist Kim Akerman however believes that the megafauna may have persisted later in refugia (wetter areas of the continent) as suggested by Wells (1985: 228) and has suggested a much younger age for the paintings.