They are best developed in the Macdonnell chain in Palaeozoic U Mesozoic Dolerite '&c. ' ® central Australia and in Victoria, where the fullest sequence is known; while they also extended north-eastward from Victoria into New South Wales, where, as yet, no Cambrian rocks have been found.
They are formed of trachyte, dolerite and basalt.
Volcanic rocks, locally called "Toadstone," are represented in the limestones by intrusive sills and flows of dolerite and by necks of agglomerate, notably near Tideswell, Millersdale and Matlock.
Serpentine into talc-schist, dolerite into hornblende-schist) by the same agencies.
These are modified forms of basic rocks such as basalt, dolerite and diabase.
In later days, in the time of the Sargonid kings of Akkad or the monarchs of Ur, stones such is granite, basalt, diorite and dolerite were probably brought from the Sinaitic peninsula, if not from the western desert of Egypt, if the Red Sea coast is to be identified, as seems very probable, with Magan, " the place to which ships went," the land whence the Babylonians got some of their first stones for sculpture and architecture.
Gudea was also a great builder, and the materials for his buildings and statues were brought from all parts of western Asia, cedar wood from the Amanus mountains, quarried stones from Lebanon, copper from northern Arabia, gold and precious stones from the desert between Palestine and Egypt, dolerite from Magan (the Sinaitic peninsula) and timber from Dilmun in the Persian Gulf.
Some of his statues, now in the Louvre, are carved out of Sinaitic dolerite, and on the lap of one of them (statue E) is the plan of his palace, with the scale of measurement attached.
They are, first, plutonic rocks, especially granite; secondly, volcanic rocks, chiefly trachyte and dolerite; and thirdly, palaeozoic schists.
Volcanic necks may be recognized at Carrick-a-rede, in the intrusive mass of dolerite at Slemish, at Carnmoney near Belfast, and a few other points.
Fair Head is formed of intrusive dolerite, presenting a superb columnar seaward face.
The dolerite of Fair Head sends off sheets along the bedding-planes of these carboniferous strata.
Immense -sheets of dolerite, gabbro, or allied basic rocks indicate eruptive materials intruded as sills or poured out as lavas contemporaneously with the sedimentary formations among which they lie.
It forms part of an intrusive mass which, on the south and west cliffs of the island, has a columnar arrangement and is traversed by dykes of dolerite, most of which run in a northwest direction.
Finally the basic dykes of dolerite, basalt and augite-andesite are abundant and traverse the various sedimentary formations and the granite.
The shores of the Bosporus are composed in the northern portion of different volcanic rocks, such as dolerite, granite and trachyte; but along the remaining course of the channel the prevailing formations are Devonian, consisting of sandstones, marls, quartzose conglomerates, and calcareous deposits of various kinds.
Thus there has been discovered in Babylon a copy of the Behistun (qv.) inscription preserved on a block of dolerite (Weissbach, Babylonische Miscellen.