Introduction
Archaean and Palaeoproterozoic
Mesoproterozoic and Neoproterozoic
Lower Palaeozoic - Cambrian, Ordovician and Silurian
Caledonian Orogeny and associated magmatism
Mostly Devonian - the Old Red Sandstone Supergroup
Carboniferous
Permian and Triassic - including the New Red Sandstone Supergroup
Jurassic and Cretaceous
Cenozoic
The surface layer