Below these is a monotonous succession of shales, practically unfossiliferous, with occasional quartzites and limestones representing the Upper and Middle Jurassic with at the base beds probably belonging to the Lias.
Associated with the limestones and calc-gneisses are quartzites and tourmaline-biotite schists which probably represent the lowest portions of the shales immediately overlying the limestones.
In Russian Poland is a series of conglomerates, quartzites and shales; Some of the beds yield a Paradoxides fauna.
In the Rennes basin limestones--often dolomitic--are associated with quartzites and conglomerates; silicious limestones also occur in the Sarthe region.
Cambrian beds of La Vega, thick quartzites with limestone, slates and iron ores.
The quartzites here form bare white cones and ridges, notably in Errigal and Aghla Mt.
The next prominent zone is that of the Ardrishaig phyllites, with quartzites in the lower portion and soft phyllites in the upper part, which cover a belt from 3 to 6 m.
The quartzites of this series form the highest hills in the south of Islay, occupy nearly the whole of Jura, and are continued in the mainland, where, by means of the rapid isoclinal folding, they form lenticular masses.
Sulphide ores in quartzites are likely to develop depressions under erosion.
For this purpose siliceous rocks, chiefly quartzites and sandstones, are ground up, mixed with lime as a binder, and fused and pressed into bricks and shapes.
Occasionally even these rocks may be extensively replaced by other minerals, as in the Coeur d'Alene district, where quartzites adjacent to the ore veins may be completely replaced by iron carbonate.
In the quartzites of the lead-silver mines of the Coeur d'Alene district of Idaho (p.
In fact even quartzite is sometimes called granite in commerce, as in the case of the Baraboo quartzites of Wisconsin, but this is going too far.
The depression had been partly filled in early geologic (probably early Paleozoic) time by sediments later deformed and metamorphosed so that they are now quartzites and shales.
Tertiary sandstones of the coastal desert with a basement of old volcanics andquartzites appearing on the valley walls.
The line of unconformity between the igneous basement rocks (agglomerates at this point) and the quartzites and sandstones of the Urubamba Valley, between the town of Urubamba and Ollantaytambo.
The sedimentary beds in the background of the first diagram are hypothetical and are supposed to correspond to the quartzites of the Majes Valley at Aplao.
The foundation rocks are old quartzites and shales in regularly alternating beds.
Farther up the Cantas valley (an hour's ride above Aplao) the Tertiary rests upon volcanic flows or older quartzites or the granite-gneiss exposed here and there along the valley floor.
These quartzites on the north shore of Quartzite lake dip regularly northwestward, away from a hill of diabase which lies to the south, and the latter therefore probably underlies the quartzite, though it is not necessarily older than it.
The pebbles in the conglomerates are well rounded and water-worn, and consist almost entirely of white clastic quartzites like that of Marble island (Huronian) beds.
The Marble island quartzites are composed of hard white quartzite, consisting of more or less rounded grains of quartz, of fairly regular size, cemented together by interstitial silica.
So these quartzites are aslant, and though of great geologic thickness they make but 800 feet of the wall.
Your books may have many-colored bindings and differ greatly in their contents; so these quartzites vary greatly from place to place along the wall, and in many places they entirely disappear.
Above thequartzites there are 500 feet of sandstones.
Good sections of thequartzites are laid bare at Rubery Station, at the village of Rubery, and in a large quarry near the roadside, a mile northward from Kendall End.
At the south-western extremity of the Lower Lickey Range the quartzites contain fragments of igneous rocks, and appear to pass down into a series of felspathic grits, pierced by dioritic dykes similar to those of the Nuneaton District.
The rocks consist of volcanic ashes, quartzites and thin-bedded shales, pierced by dioritic dykes.
In the last-named locality the quartzites are seen greatly folded and faulted.
The Bokkeveld beds are conformably succeeded by the sandstones, quartzites and shales of the Witteberg series.
The Ongeluk volcanic series, consisting of lavas and breccias, conformably overlies the Griquatown series; while the grits, quartzites and conglomerates of the Matsap series rest on them with a great discordance.
Well-developed quartzites with slates and diabases are found south of Yarkand and Khotan.
Most of these are aggregated together in coprolites and quartzites (jasper, chert, flint, &c.
From conversations with this estimable palaeontologist I have learned, however, that he has pursued his fruitful investigation of the Mesozoic quartzites (s 243), and has met with no less success in the case of similar Palaeozoic structures.
Now climb 800 feet and a point of view is reached where the variegated quartzites are seen.
So these quartzites are aslant, and though of great geologic thickness, they make but 800 feet of the wall.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "quartzites" in a variety of sentences. We hope that you will now be able to make sentences using this word.
