Banks Wall Sandstone is a type of

sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...

occurring in the

Sydney Basin The Sydney Basin is an Interim Biogeographic Regionalisation for Australia, interim Australian bioregion and is both a structural entity and a depositional area, now preserved on the east coast of New South Wales, Australia and with some of its ...

in eastern

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. This stratum is up to 115 metres thick. Often seen in the Blue Mountains, such as at the Three Sisters at

Katoomba Katoomba is the main town and council seat of the City of Blue Mountains in New South Wales, Australia, and is the administrative centre of Blue Mountains City Council. Situated on the Great Western Highway and the Great Western Railway, Kato ...

. The rock is mostly

quartzose Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical fo ...

, but also contains many

ironstone Ironstone is a sedimentary rock, either deposited directly as a ferruginous sediment or created by chemical replacement, that contains a substantial proportion of an iron ore compound from which iron (Fe) can be smelted commercially. Not to be c ...

bands, with conglomerates and numerous

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone and shale. Most of the particles of which the stone is composed are less than and are too small to ...

lenses A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...

several metres thick. It is situated above the Mount York Claystone. Formed in the early

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

, it is part of the Narrabeen Group of sedimentary rocks

References

Geologic formations of Australia Triassic Australia Sandstone formations Geology of New South Wales {{Australia-geology-stub

See also

References