The Trias proper is represented by truly marine deposits, while the rhaetic beds contain plant remains.
Microlestes is a rhaetic genus, known from rocks in Germany and England; but it is entirely based upon molar teeth.
Contemporaneous volcanic rocks are associated with the Ordovician beds and with the rhaetic sandstones in several places.
This limestone occurs in irregular masses near the base of the White Lias, or uppermost division of the rhaetic series.
Elsewhere the plants generally indicate a higher horizon and are considered to correspond with the rhaetic of Europe.
The rhaetic beds which follow the Keuper mark the incoming of the sea and introduce the fossiliferous Liassic deposits.