Terrigal Formation

The Terrigal Formation is a geologic formation in the Sydney Basin in eastern Australia. Commonly seen in the Central Coast region, this stratum is up to 330 metres thick. Formed in the early to mid Triassic,^[1] it is part of the Narrabeen Group of sedimentary rocks. This formation includes interbedded fine to medium-grained sandstone and siltstone, with minor deposits of claystone. Hawkesbury Sandstone occasionally overlies the Terrigal Formation.^[2][3] Numerous fossils are known from this area, including the temnospondyl amphibians Arenaerpeton supinatus^[4] and Platycepsion wilksoni.

Terrigal Formation
Stratigraphic range: Olenekian-Anisian ~248.1–244.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Terrigal, Central Coast, Australia
Type	Geological formation
Unit of	Narrabeen Group
Underlies	Hawkesbury Sandstone
Thickness	up to 330 metres (1,080 ft)
Lithology
Primary	Sandstone and siltstone
Other	Claystone
Location
Region	New South Wales
Country	Australia
Extent	Sydney Basin

See also

• Sydney Basin
• Munmorah Conglomerate
• Newport Formation
• Narrabeen group