The Cliefden Caves is a heritage-listed geoheritage site at Mandurama, in the Central West region of New South Wales, Australia.

[7] Geologists around the world regard it as a superb example of an Ordovician island faunal assemblage[8] By the 1950s, the Cliefden caves had become popular with speleological groups.

The book "Australia's fossil heritage" states that "The site is unusual because of the well exposed, diverse faunas showing the progression from near-shore to deep water marine environments.

The Cliefden Caves - Belubula River Valley sites contain the best exposures of Late Ordovician island marine invertebrate fossil assemblages in Australia.

The region surrounding the Cliefden Caves is an internationally significant palaeontological and geological site that records the evolution of a tropical volcanic island over an interval of about 5 million years, from the development of a fringing lagoonal and atoll to its eventual subsidence and drowning.

More than 90 karst features have been identified, including well-developed caves, dolines, tufa deposits and a warm (thermal) spring.

The speleothems at Cliefden range in colour from clear through pure white, yellow to orange and several rare formations of sky-blue and aqua green.

All the major caves are locked and gated to protect them, however speleological and scientific work is allowed under a strict permit system.

Studies of the Tufa (calcite) deposits on Davis Creek have contributed to knowledge of the late Holocene period change.

Grazing pressure and other human activity over 175 years have had profound impacts on the endemic flora of the region, especially the karst-specific species and communities at Cliefden, which remain poorly conserved.

[2] The caves system and surface exposures of the fossil beds remain intact and retain a high degree of integrity, despite increasing pressure from over-collecting of specimens.

In some cases, these features are of regional and state significance, highlighting the importance of all karst environments, whether publicly or privately managed."

The report also states that "Thermal springs ... are rare in NSW and, besides Wee Jasper, occur only at Cliefden and Yarrangobilly caves.

The construction of a dam at the Needles Gap site on the Belubula River will completely flood most of the caves, destroying their heritage value and preventing future study.

Carthew and Drysdale [16] demonstrated that it was possible to use information from the tufa deposits to construct a history of stream development in Davys Creek.

[19] Warm springs rising from Palaeozoic rock (as opposed to those from the Australian Basin) are rare in NSW, with only three documented, all in karst areas.

The site most mentioned is at The Needles, where the river has cut a narrow gap through a resistant zone of conglomerates, quartzite and sandstones.

The area provides evidence of a lithological/sedimentological sequence that contributes to the understanding of the geological evolution of eastern Australia at a time when that part of the continent was submerged in the palaeo-Pacific Ocean.

[2] The area is important for its social values, being spiritually significant to Waradjuri traditional owners who continue to visit the site for ritual purposes and cultural obligations to the land.

[2] Cliefden Caves Area - Natural and Cultural Landscape was listed on the New South Wales State Heritage Register on 30 August 2017 having satisfied the following criteria.

The fossils record also defines biogeographic affinities in places that are now quite remote from each other, for example, the genus Belubula is found only in Cliefden and Zhuhuia in South China, providing evidence that during the Ordovician period these regions were situated far closer together than their present geographic setting, having separated as a result of subsequent plate tectonic movement.

The system contains an extensive range of karst features, including caves, dolines, tufa deposits and a warm (thermal) spring.

The speleothems at Cliefden range in colour from clear through pure white, yellow to orange and several rare formations of sky-blue and aqua green.

The Wiradjuri people retain a strong connection to the place, using the caves for ritual purposes, visiting the hot spring, collecting coloured ochres and fishing for native species in the Belubula River.

The Cliefden Caves Limestone Group is the subject of current, ongoing research in the areas of paleontology, karst processes, climate change, geology, hydrology and archaeology.

[2] The region has been the subject of several palaeontological field excursions associated with major international scientific conferences held in Sydney and Orange over the past three decades.

As a direct result of these field trips, ongoing collaborative research projects into various aspects of the fossils from this area have been established between NSW palaeontologists and those from China and the Czech Republic.

[2] The well-preserved geomorphic evidence of the Belubula Valley and the Cliefden Caves record of the area's hydrogeology, have the potential to yield further information on the landscape evolution of the Eastern Highlands.

Ordovician rocks in the Cliefden area contain many fossils unique to Australia and occasionally unknown elsewhere in the world, such as the brachiopod species Belubula spectacula.

[2] This Wikipedia article contains material from Cliefden Caves Area - Natural and Cultural Landscape, entry number 01996 in the New South Wales State Heritage Register published by the State of New South Wales (Department of Planning and Environment) 2018 under CC-BY 4.0 licence, accessed on 2 June 2018.