The Evergreen Formation is a Pliensbachian to

Toarcian The Toarcian is, in the International Commission on Stratigraphy, ICS' geologic timescale, an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic. It spans the time between 184.2 Megaannum, Ma (million ...

geologic formation of the Surat Basin in

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

and

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

, eastern Australia. Traditionally it has been considered to be a unit whose age has been calculated in between the Pliensbachian and

stages of the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic� ...

, with some layers suggested to reach the Aalenian stage of the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

, yet modern data has found that an Early Pliensbachian to Latest Toarcian age is more possible. 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. This unit overlies the

Hettangian The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triass ...

Sinemurian In the geologic timescale, the Sinemurian is an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between 199.5 ±0.3 annu ...

Precipice Sandstone, as well several informal units such as the Nogo Beds, and Narayen beds, as well Torsdale Volcanics. This unit likely was deposited in a massive lacustrine body with possible marine environment influences. __TOC__

Fossil content

Ichnofossils

Diplopoda

Vertebrata

Phytoplankton

Bryophyta

Lycophyta

Pteridophyta

Peltaspermales

Cycadophyta

Conifers

References

Further reading