The Mittagong Formation is a sedimentary rock unit in the Sydney Basin in eastern Australia.
Formation Laid down in the Triassic Period, it may be seen as an interval of interbedded fine-grained sandstone and shale between the Ashfield Shale (above) and the Hawkesbury sandstone (below). The maximum thickness around Sydney may be ten metres. Near Town Hall railway station, the formation is 8 metres thick. In the type area at Mittagong it is 15 metres thick.
Whereabouts In northern Sydney it can be seen in several areas, such as West PymbleField Geology of New South Wales, Sydney Basin page 102 and Mount Ku-ring-gai.Chris Herbert. Geology of the Sydney 1:100,000 Sheet 9130 This rock formation is associated with the critically endangered Sydney Turpentine-Ironbark Forest.
See also Narrabeen group
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