Porphyrite Sentence Examples
The Old Man presents a characteristic section, for it exhibits a thick pile of massive, current-bedded red sandstones, resting, near the foot of the pinnacle, upon a thin bed of amygdaloidal porphyrite, which in its turn lies unconformably upon steeply inclined flagstones.
In China, at the close of the period, there were enormous eruptions of melaphyre, porphyrite and quartz-porphyry.
Their geological formation is metamorphic gneiss, veined with felspar and quartz, and interspersed with reddish porphyrite.
The deposits are marine, consisting mainly of sandstone and limestone, together with tuffs and conglomerates of porphyry and porphyrite.
They comprise Seil, Easdale, Torsay, Luing and Shuna, and owe their name to the fact that they are composed mainly of metamorphic rocks, Easdale, Torsay and Luing being entirely slate, Seil mostly slate with some porphyrite in the north, and Shuna gneissose.Advertisement
There occur also quartz-porphyry (Sierra Morena, Pyrenees, &c), diorite, porphyrite, diabase (well developed in the north of Andalusia, where it plays a great part in the structure of the Sierra Morena), ophite (Pyrenees, Cadiz), serpentine (forming an enormous mass in the Serrania de Ronda), trachyte, liparite, andesite, basalt.