anticline ardennes avalonia belgium blisworth limestone borehole brittany cambrian carboniferous clime continental drift continental shelf cretaceous derbyshire devon devonian dinantian east anglia equator erosion estuary france french language geologic time scale great britain jurassic laterite latitude leicestershire lincolnshire lower estuarine series market weighton axis namib desert new red sandstone norfolk nottinghamshire oceanic crust old red sandstone ordovician permian precambrian proterozoic rhineland river thames rutland silurian soil stratum swamp terrane variscan orogeny westphalia widmerpool gulf yorkshire