Thus western Europe in early Carboniferous time was occupied by a series of constricted, gulf-like seas; and on account of the steady progress of intermittent warping movements of the crust, we find that the areas of clearer water, in which the limestone-building organisms could exist, were repeatedly able to spread, thus forming those thin limestones found interbedded with shale and sandstone which occur typically in the Yoredale district of Yorkshire and in the region to the north, and also in the culm deposits of central Europe.
Near Lithgow extensive deposits of limonite, or clay-band ore, are interbedded with coal.
The slates are interbedded with limestones containing fossil brachiopods, which have led to their determination as Silurian or Devonian; but L.
In the district around Port Glasgow, on the south coast of the eastern peninsula, are the Boioro limestones, also of unknown age; they are lead-coloured, brecciated limestones with interbedded dolerites.
These Cretaceous limestones are interbedded with glauconitic greensands, as at Moeraki Point in eastern Otago.