the world > the earth > structure of the earth > age or period > [adjective] > primary or Palaeozoic > Permo-carboniferous (3)
Esp. of certain Palaeozoic formations in the Czech Republic and North America: forming a transition between the Carboniferous and Permian…
In Geology used by different writers in various senses, with allusion to the Harz Mountains. Of, pertaining to, or contemporaneous with the…
The late Pennsylvanian and early Permian systems or periods considered jointly.