Some igneous rocks, especially lavas, are glassy; others are so fine grained that the crystals cannot be seen.
Igneous rocks, while still molten, have been forced into other rocks from below, or poured out on the surface from volcanoes.
The foundation of the island is formed of metamorphic and igneous rocks, which appear in the Sierra Maestra and are exposed in other parts of the island wherever the comparatively thin covering of later beds has been worn away.
All these forms are found in vitreous igneous rocks.
They are common constituents of microcrystalline igneous rocks, and often occur as inclusions in larger crystals of other substances.
Every metal deprived of this igneous principle is immediately reduced to a calx, and thus deprived of its splendour, fusibility, and other properties, until restored again by the readmission of its phlogiston.
We had reached the village of Hassané, opposite to a conical hill named Chisulwé, which is on the south side of the river, and evidently of igneous origin.
As at Chilolé hill, we haveigneous rocks, apparently trap, capped with masses of beautiful white dolomite.
As we come down from the watershed towards Tanganyika we enter an area of the earth's surface still disturbed by internal igneous action.
The abundance of melanite is very unusual in igneous rocks, though some syenites, leucitophyres, and aegirine-felsites resemble borolanite in this respect.
In the Sanquhar basin there are small outliers of lavas probably of this age and several vents filled with agglomerate from which these igneous materials in the Thornhill basin may have been derived.
His attention was now largely directed to the study of the artificial production of minerals, to the metamorphism of rocks, and to the genesis of igneous rocks.
Some of the vents from which these igneous materials may have been discharged are found along the watershed between Liddesdale and Teviotdale in Roxburghshire.
In 1857 he published his famous Essai de petrologie comparee, in which he expressed the view that the igneous rocks have been derived from two magmas which coexist beneath the solid crust, and are respectively acid and basic.
Land forms due directly or indirectly to igneous action and the influence of rock character on the determination of land forms are subjects of special chapters.
This leads to the distinction between the igneous and the subaqueous, the volcanic, plutonic, and metamorphic, and the derivative rocks on which epigene agencies have performed their shaping work.
The lake lies among the outer spurs of the Alps that divide the Ticino (Tessin) basin from that of the Adda, where the calcareous strata have been disturbed by the intrusion of porphyry and other igneous rocks.
There is now no doubt that these rocks, with those on the adjacent moorland of Slieve Gullion, belong to the early Cainozoic igneous series, and may be compared with similar masses in the Isle of Skye.
The two powers of igneous and lunar lights are represented in the conjoined bodies of the Agni soma deities).
The mineral is occasionally found as concretionary masses (sphaerosiderite) in cavities in basic igneous rocks such as dolerite.
Bouley Bay; a complex igneous and intrusive series of rocks lies around St Helier.
A dark green igneous rock, consisting largely of chrysolite, with hornblende, augite, biotite, etc.
One who adopts the geological theory ofigneous fusion; a Plutonian.
Pyroxene is an essential constituent of many rocks, especially basic igneous rocks, as basalt, gabbro, etc.
Rocks, except certain glassy igneous forms, are either simple minerals or aggregates of minerals.
Produced by a volcano, or, more generally, by igneous agencies; as, volcanic tufa.
Defn: An igneous rock,usually light gray in color and breaking with a rough surface.
Defn: One who adopts the geological theory of igneous fusion; a Plutonian.
Defn: A mass of igneous rock intruded between sedimentary beds and resulting in a mammiform bulging of the overlying strata.
Defn: An igneous rock consisting essentially of plagioclase and either leucite or nephelite, or both.
Defn: Resulting from, or produced by, the action of fire; as, lavas and basalt are igneous rocks.
Defn: Produced by eruption; as, eruptive rocks, such as the igneous or volcanic.
Defn: A column of igneous rock formed by congelation of lava in the conduit of a volcano and later exposed by the removal of surrounding rocks.
Of the igneous rocks, those classed as trap are best known to the road builder and many of the deposits of trap rock afford an excellent material for broken stone roads where the severest conditions of traffic are encountered.
Many varieties of rocks are to be found among the gravel pebbles, but the rocks of igneous origin and possessing a considerable degree of hardness generally predominate.
The harder limestones, some sandstones, pebbles from many of the gravel deposits and practically all of the igneous rocks make satisfactory aggregates for the concrete road.
In many places, especially on the islands of the northern Marianas there is little soil; there are large areas of bare igneous rock, because the islands are geologically of relatively recent origin and little erosion has occurred.
The igneousrocks found on these strewn islands are basaltic in nature.
Other strewn islands consist of igneous rocks which are exposed above the surface of the ocean.
This was the first igneous rock of more recent date, that we had met with since leaving Separation Creek, and the upper Lynd.
The creek here consists of a close chain of fine rocky water-holes; the rock is principally clay, resembling very much a decomposed igneous rock, but full of nodules and veins of iron-stone.
The ridges, near the water-holes on which we were encamped, are composed of an igneous rock containing much iron, with which the water was impregnated to such a degree, that our tea turned quite black and inky.
The ranges were composed of a Psammite, which was frequently baked, probably by neighbouring out-bursts of igneous rock.
The sand in the bed of the river contains very minute particles of igneous rock.
The whole country I had travelled over, is composed of sandstone, with probably occasional outbreaks of igneous rocks, as indicated by the rich black soil.
Artificial sapphires have been made of a fair size and perfectly transparent by the addition of cobalt to the igneous bath of alumina, but the writer does not consider them equal in colour to true Oriental sapphire.
It is evident that if to the igneous bath of alumina some colouring matter, such as manganese, is added capable of communicating a violet colour to the crystals of alumina, the Oriental amethyst will be the result.
The unstratified class are all colored red, to indicate their igneous origin.
It may be thought, however, that the igneous fluidity of the internal part of the globe is too mighty and improbable a conclusion to be based upon the increase of temperature, observed only to the depth of two or three thousand feet.
I must acknowledge, however, that all these arguments fail of convincing a few geologists of the doctrine of internaligneous fluidity, to the extent above described.
To prove the original igneous fluidity of the globe, we might have adopted another course of argument.
The conversion of the igneous liquid surface into solid matter, could only have taken place in successive shells or concentric layers; hence would arise a stratified character.
But we, even to the present day, occasionally see the igneous fluid from beneath forced up to the surface, and spreading from volcanic craters over great regions.
Such, however, will not be the termination of the present order of things; we are taught to look for this in an igneous eruption, the source of which now slumbers almost quiescent beneath our feet.
The trap rocks themselves may have been formed in a similar manner, by upward pressure of the igneous fluid beneath, through the veins and fissures formed on the breaking of the solid crust.
I have shown specimens of this incrustation to several geologists, and they all thought that they were of volcanic or igneous origin!
Mammoth trees Marco Polo Marsh gas Medium oils Metamorphism of coal by igneous agency Methods of ventilation Mountain limestone Murdock's use of gas Mussel beds N.
Owing to the great igneous and volcanic activity at the close of the deposition of the carboniferous system of strata, the coal-measures exhibit what are known as faults in abundance.
This hypothesis is so much the more probable, because in this fire-scathed region the lake affords manifest indications of an igneous travail even now accomplishing itself sullenly in the bowels of the globe.
Streams eroded the hard igneous and metamorphic rocks from this ancient landmass and dumped the material into basins to the northeast and southwest.
During the Miocene Epoch igneous rock welled up into older rocks to form the cores of the nearby La Sal, Abajo, and Henry Mountains.
In addition to the Precambrian igneous and metamorphic rocks, there is about 2,000 feet of Paleozoic sedimentary rocks older than the Pennsylvanian Paradox Member of the Hermosa Formation, most of which was laid down in ancient seas.
They assured us that igneous meteors were extremely rare on those coasts after two o'clock in the morning.
Igneous phenomena of the mountain of Cuchivano, near Cumanacoa.
The oblong bubbles observed in the obsidians of every continent are incontestible proofs of their ancient state of igneous fluidity; and Dr.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "igneous" in a variety of sentences. We hope that you will now be able to make sentences using this word.
