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.
The Eocene beds are nummulitic. There is a lacustrine group which has usually been placed in the Lower Eocene, but the discovery of Anthracotherium magnum in the interbedded lignites proves it to be Oligocene, in part at least.
The mountains consist here of an ancient laminated micaceous quartzite, which is in parts a flexible sandstone known as itacolumite, and in parts a conglomerate; it is interbedded with clay-slate, mica-schist, hornblende-schist and haematite-schist, and intersected by veins of quartz.
Ormuz series; lavas and tuffs with interbedded cla y s and sandstones.
Griesbach, basic volcanic rocks are interbedded with the lowest part of the plant-bearing series, and enormous outbursts took place during the Neocomian period.
They are interbedded with unfossiliferous sandstones and shales.
In the Rajmahal Hills basaltic lava flows are interbedded with the Gondwana deposits, and in the Karharbari coalfield the Gondwana beds are traversed by dikes of mica-peridotite and basalt, which are supposed to be of the same age as the Rajmahal lavas.
An extensive literature has grown up relating to these Laramie strata, for owing to the Tertiary aspect of the contained plants, geologists were slow to recognize that they could be truly contemporaneous and interbedded with others yielding Cretaceous animals.
These mountains consist of detached remnants of a sheet of quartz conglomerates, interbedded with sandstones, containing crinoid stems and obscure brachiopods.
The chief rocks of the Campbell Rand series are limestones and dolomites, with some interbedded quartzites.