Banks Wall Sandstone is a type of

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

occurring in the Sydney Basin in eastern Australia. This stratum is up to 115 metres thick. Often seen in the Blue Mountains, such as at the Three Sisters at Katoomba. The rock is mostly quartzose, 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 con ...

bands, with conglomerates and numerous claystone

lenses A lens is a transmissive optical device which 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 ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...

, it is part of the

Narrabeen Group The Narrabeen group of sedimentary rocks occurs in the Sydney Basin in eastern Australia. This series of rocks was formed in the Triassic Period. Geology It includes various rock types including lithic sandstone, quartz sandstone, siltstones, ...

of sedimentary rocks

References

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

See also

References