On an Intrusion of Muscovite-biotite gneiss in the S.
The mountains of mica-slate and gneiss in Peru and New Grenada immediately touch the volcanic porphyries of the provinces of Quito and Pasto.
The rising of the gneiss and mica-slate strata to the south appears to me to explain in a considerable degree the extreme humidity of the coast.
It is in the mountains of Buenavista that the gneissmanifests a tendency to pass into eurite.
Examining the mosses which cover the rocks of gneiss in the valley between the two peaks, I was surprised at finding real pebbles,--rounded fragments of quartz.
The granite superposed on the gneiss does not present a regular separation into beds: it is divided by clefts, which often cross one another at right angles.
The primitive limestone above the spring of Sanchorquiz, is directed, as the gneiss in that place, hor.
Germany to the most metalliferous rocks; but in the New Continent, the gneiss has not hitherto been remarked as very rich in ores worth working.
The gneiss as far as this spot preserves its lamellar texture and its primitive direction; but where we climbed the summit of the Silla, we found it had passed into granite.
This rounded summit, and the ridge of Galipano crenated like a wall, are the only objects which in this basin of gneiss and mica-slate impress a peculiar character on the landscape.
The direction of the strata of gneiss varies; it is either hor.
This wall, at first sight purposeless, proved to be in fact a stone ladder, the flakes of gneiss which projected along its top serving as steps for the active peasantry.
The travelers sat down on a low rock of gneiss to rest themselves, and then and there did the King of Borva recite his grievances and rage against the English smacks.
At last he ventured to ask whether there were any fossils in the blocks of gneiss that were scattered over the moorland.
Everywhere around were the traces of this glacier drift--great gray boulders of gneiss fixed fast into the black peat moss, or set amid the browns and greens of the heather.
Geologically, they have also been differentiated as the Gneiss Islands and the Trap Islands.
The Outer Hebrides being almost entirely composed of gneiss the epithet suitably serves them, but, strictly speaking, only the more northerly of the Inner Hebrides may be distinguished as Trap Islands.
The beach consisted of large rolled stones of gneiss and syenite{7}, amongst which many pieces of ice had grounded, and it was with difficulty that we effected a landing in a small cove under a steep cliff.
But the borders of Lower Carp Lake, where the gneiss formation prevails, are composed of hills, having less altitude, fewer precipices, and more rounded summits.
The accommodation and food in San Demetrio leave much to be desired; its streets are irregular lanes, ill-paved with cobbles of gneiss and smothered under dust and refuse.
There is the same smiling alternation of woodland and meadow, the same huge boulders of gneiss and granite which give a distinctive tone to the landscape, the same exuberance of living waters.
The consolidation of this stratum produced the gneiss formation.
The gneiss formation, as already observed, was the result.
These beds I conceive, when consolidated, to constitute the gneiss formation.
The rocks of Ceylon are primitive, consisting of granite, gneiss and quartz.
The soil abounds with rocks of gneiss and quartz, some of the latter rose-color, some pure white.
This gneiss rock, when in a peculiar stage of decomposition, has the appearance and consistency of yellow brick, speckled with plumbago.
It exists in such quantities, in the gneiss rocks that upon their decomposition it is seen in bright specks like silver throughout.
The scenery is charming, lofty hills of trap rock, with unusually rich slopes (for the 70th parallel) descending to the fiord, and strewed with boulders of gneiss and granite.
In this locality a quartziferous black mica schist underlies the Silurian limestone, and is interstratified with gneiss and garnetiferous quartz rock, all in beds, inclined 38 deg.
It is composed of quartz, red felspar, and dark green chlorite; and is accompanied with gneiss of the same composition.
The greater part are still standing; they consist, with a few exceptions, of a single piece of gneiss in the rough state in which they were quarried.
A few paces from this was a single pillar of gneiss in a rough state, which was from fourteen to sixteen feet high.
Gneiss is beyond question the most prevalent rock, and we seem justified in assigning the peculiar monotony of the Outer Hebridean scenery to that fact.
Occasionally the "lines" are so close that the clay sometimes presents the appearance of rude and often wavy and irregular lamination--a section of such a boulder-clay reminding one sometimes of that of a gnarled gneiss or crumpled schist.
When we study the manner in which the gneiss and gneissic rocks disintegrate and break up at the sea-coast or along the flanks of some rugged mountain-glen, we see they give rise to an irregular uneven surface.
In regions of gneiss and granite the mountains are usually rounded and lumpy in form.
Now and again, however, the gneiss gives place to granite, as on the west coast of Lewis near Carloway; and here and there the strata are pierced by vertical dykes and curious twisted and reticulated veins of basalt-rock.
It is a truly eruptive rock, occurring in intrusive bosses, or in beds interstratified with gneiss and mica-schist, and owes its various shades of green to the presence of copper.
The pebbles were derived from the central nucleus of granite from beyond Assouan to the upper end of the Red Sea, round which are folded successive zones of gneiss and schist pierced by intrusive masses of porphyry and serpentine.
Underneath this canopy, in the centre of a huge mass of gneiss and hornblende, forming the living rock, there is the rude outline of a gigantic foot about five feet long, and of proportionate breadth.
The contacts of the olivine rocks with gneiss usually produce rich deposits.
Most of the supply of cryolite comes from Greenland, where it occurs in veins running through gneiss rocks.
However, much of the rock of the valley partakes of the nature of both hornblend and gneiss, and has been aptly termed a "hornblend gneiss rock.
The gneiss from the quartz it contains makes a sandy soil, while the clay slate gives it tenacity.
The aspect of the rock at this stage is that of a gneiss with rather indefinite banding.
Along the eastern side of the valley (Loudoun) gneiss is frequently met with on the surface, and where the larger streams have worn deep valleys, it is sometimes exposed in high and precipitous cliffs.
Beyond these rocks lay Maitre Ile, all gneiss and shingle, a desert in the sea.
These were known as the Colombiere, the Grosse Tete, Tas de Pois, and the Marmotiers; each with its retinue of sunken reefs and needles of granitic gneiss lying low in menace.
The finest of the valleys stretching inland from the fiords is Romsdal, where the rounded pure gneiss mountains tower up to six thousand feet with almost perpendicular walls.
Thus gneissappears to be formed by the disintegration of granite.
Garnet is a very common mineral in gneiss and mica slate.
Gneiss approaching to mica-slate, felspar white, and in small quantity.
The town is built on a low bank of gneiss and micaceous slate which runs out into the sea and affords some protection at the landing-place against the violence of the surf.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "gneiss" in a variety of sentences. We hope that you will now be able to make sentences using this word.
