"There are no certain ways to date individual cylcons. The oldest cylcon/message stone found in a dateable archaeological context is about 20,000 years old. The simple line motifs of the oldest cylcons represent the earliest art of the Aborigines, from a very early period of occupation. In Australian nomenclature this is the colonizing period, or early Stone Age, ca. 50,000/40,000-3,000 BC. With the earliest rock-carvings and paintings, the cylcons represent the oldest form of communication and art; and they represent the oldest religion still observed. Only 2 Aborigines have been able to communicate their name of the cylcons: Yurda, and Wommagnaragnara (Heart of the snake), respectively. Other uses as tallies are possible, such as counting of dead people, warriors, emus, measures of nardo seeds, or mapping purposes counting day-marches in various directions. Later the use could also change to other magic rituals, some involving the chipping off smaller flakes, and the practical use for pounding and crushing. Much more research is needed before the cylcons' real age and significance can be properly understood and appreciated.
"The term cylcon is derived from the title of R. Ethridge's publication: The Cylindro-conical and Stone Implements of Western New South Wales and their significance. Ethnological Series No. 2, Memoirs of the Geological Survey of New South Wales, 1916:1-41" (http://www.schoyencollection.org/religionsLiving.html, accessed 03-06-2009)