The other rocks include igneous breccias, shales, coarse conglomerates and grits.
Another group of phosphatic deposits connected with igneous rocks comprises the apatite veins of south Norway, Ottawa and other districts in Canada.
The lower part of the Keweenawan system consists of a great succession of lava flows, of prodigious thickness.- This portion of the system is overlain by thick beds of sedimentary rock, mostly conglomerate and sandstone, derived from the igneous rocks beneath.
In North America, the principal region of volcanic activity lay in the west; great thicknesses of igneous rocks occur in the Lower Carboniferous rocks of British Columbia, and from the middle of the period until near its close volcanoes were active from Alaska to California.
Thus he carried on the narrative of orderly development from the point at which it was left by Kant and Laplace - explaining by reference to the ascertained laws of physics and chemistry the configuration of the earth, its mountains and seas, its igneous and its stratified rocks, just as the astronomers had explained by those same laws the evolution of the sun and planets from diffused gaseous matter of high temperature.
The northern coast range is formed by the oldest rocks in the island, consisting chiefly of limestones and marbles with occasional masses of igneous rock.
The ordinary accessory minerals of igneous rocks, apatite, in Great Britain and the continent of Europe.
The central, southern and eastern Highlands are occupied by metamorphosed sedimentary and igneous rocks, to which has been provisionally assigned the name of Dalradian, from the old Celtic kingdom of Dalriada.
The fossils from the Rhaetic beds belong to the Avicula contorta zone, those from the Lias to the Ammonites angulatus zone, while the blocks of limestone with chert contain Inoceramus, Cretaceous foraminifera and other organisms. The materials yielding these fossils are embedded in a course volcanic agglomerate which gives rise to crags and is pierced by acid and basic igneous ricks.
The foothills and lowlands throughout southern Wicklow and almost the whole of Wexford, and the corresponding country of western Wicklow and eastern Kildare, are thus formed of Silurian beds, in which numerous contemporaneous and also intrusive igneous rocks are intercalated, striking like the chain N.E.