East of Bolsover, the Coal Measures are covered uncomformably by the Permian breccias and magnesian limestone.
East of Bolsover, the Coal Measures are covered unconformably by the Permian breccias and magnesian limestone.
Upper: Red and grey sandstones, marls and clays with occasional breccias, thin coals and limestones with Spirorbis, workable coals in the South Wales, Coal Bristol, Somerset and Forest of Dean coalfields.
They consist of breccias, conglomerates, sandstones, marls, and limestones, with seams of coal and lignite.
It is only in the more northerly part of the country that the pipes are filled with blue ground (or " kimberlite "), and that they are diamantiferous; but over a great part of Cape Colony have been discovered what are probably similar pipes filled with agglomerates, breccias and tuffs, and some with basic lavas; one, in particular, in the Riversdale Division near the southern coast, being occupied by a melilite-basalt.
There occur also below the Lias on some parts of the west coast unfossiliferous red sandstones, conglomerates and breccias, presenting lithological resemblance to the Rhaetic group of England.
These are overlaid by sandstones, slates and limestones, alternating with porphyries and porphyrites, sometimes in the form of sheets, sometimes as breccias and conglomerates.
These are overlain, perhaps unconformably, by a great thickness of lavas and volcanic breccias (Pniel volcanic series, Beer Vley and Zeekoe Baard amygdaloids), and these in turn by the quartzites, grits and shales of the Black Reef series.
The Ongeluk volcanic series, consisting of lavas and breccias, conformably overlies the Griquatown series; while the grits, quartzites and conglomerates of the Matsap series rest on them with a great discordance.
The principal varieties are basalt and palagonitic breccias, the former covering two-thirds of the entire area, the latter the remaining one-third.
The palagonitic breccias, which stretch in an irregular belt across the island, are younger than the basalt.
The palagonitic breccias, which attain their greatest development in the south of the island and on the tableland, consist of reddish, brown or yellowish rocks, tuffs and breccias, belonging to several different groups or divisions, the youngest of which seems to be of a date subsequent to the Glacial epoch.
In the middle of Iceland, where the geological foundation is tuff and breccias, large areas are buried under ancient outflows of lava, which bear evidences of glacial scratching.