The median zone is composed largely of crystalline rocks with granites and some palaeozoic unfossiliferous rocks.
Occur exclusively in palaeozoic strata from Devonian upwards.
It belongs to the oldest, or palaeozoic, system of formations.
This has been particularly the case with the group of palaeozoic corals formerly classed together as Rugosa.
They are however certainly Pre-Permian, and it is most probable that they belong to the early part of the palaeozoic era.
Carboniferous beds occur in the north of the palaeozoic area.
He might have as well said that love existed during the secondary or palaeozoic periods.
There is also amongst the palaeozoic group an interesting series of red slates containing Radiolaria.
The Tetrabranchiata were most abundant in the palaeozoic and Mesozoic periods.
It is not till Silesia that the palaeozoic formations again rise to the surface.