Located along the Belubula River, the Cliefden karst environment includes one of the most significant cave systems on private land in New South Wales and is also the site of the first discovery of limestone on mainland Australia in 1815. There are approximately 100 individual caves at Cliefden, which contain diverse speleothems, including rare pale-blue formations. There is also an abundance of fossil deposits. The stamp features the beautiful golden stalactites and stalagmites of the highly decorated Clown Room in Cliefden Main Cave.
Australia 2017, Undara Lava Tube.
The stamps were issued in the series "Caves".