The Evergreen Formation is a Pliensbachian to Toarcian geologic formation of the Surat Basin in New South Wales and Queensland, eastern Australia. Traditionally it has been considered to be a unit whose age has been calculated in between the Pliensbachian and Toarcian stages of the Early Jurassic, with some layers suggested to reach the Aalenian stage of the Middle Jurassic, yet modern data has found that an Early Pliensbachian to Latest Toarcian age is more possible.[4][5][6] The formation was named due to the "Evergreen Shales", defined with a lower unit, the Boxvale Sandstone, and a partially coeval, partially younger upper unit, the Westgrove Ironstone Member.[7] This unit overlies the Hettangian-SinemurianPrecipice Sandstone, as well several informal units such as the Nogo Beds, and Narayen beds, as well Torsdale Volcanics.[7] This unit likely was deposited in a massive lacustrine body with possible marine environment influences.[8]
^Todd, Christopher N.; Roberts, Eric M.; Knutsen, Espen M.; Rozefelds, Andrew C.; Huang, Hui-Qing; Spandler, Carl (December 2019). "Refined age and geological context of two of Australia's most important Jurassic vertebrate taxa (Rhoetosaurus brownei and Siderops kehli), Queensland". Gondwana Research. 76: 19–25. Bibcode:2019GondR..76...19T. doi:10.1016/j.gr.2019.05.008.