Principal Subdivisions of the Carboniferous Group. — Different
Thickness of the sedimentary and calcareous Members in Scotland and the
South of England. — Coal-measures. — Terrestrial Nature of the Growth
of Coal. — Erect fossil Trees. — Uniting of many Coal-seams into one
thick Bed. — Purity of the Coal explained. — Conversion of Coal into
Anthracite. — Origin of Clay-ironstone. — Marine and brackish-water
Strata in Coal. — Fossil Insects. — Batrachian Reptiles. —
Labyrinthodont Foot-prints in Coal-measures. — Nova Scotia
Coal-measures with successive Growths of erect fossil Trees. —
Similarity of American and European Coal. — Air-breathers of the
American Coal. — Changes of Condition of Land and Sea indicated by the
Carboniferous Strata of Nova Scotia.