It must be admitted, however, that the term "coal" is here being extended to only partially fossilized vegetation of younger geological age than true coal, and to bituminous shales of various ages.
Shales of this kind often contain as much as 80 to 90 per cent.
Bituminous shales of different kinds are distilled at a low red heat in iron retorts, and from the volatile portions there are separated those valuable products which have already been alluded to, viz.
The shales worked are approximately of the same age as true coal, i.
We may fairly claim these as coal products, although the shales used contain much mineral matter, the carbon averaging about 20 per cent.
It is stained a vivid red by the wash of the red Supai shales above.
McElmo Formation 800 Lower Shales and sandstones of many Cretaceous colors.
Recently, however, it has been proved that some of the bands in the Wardie shales give a low yield of oil and sulphate of ammonia.
The pebbles of the basal conglomerates are derived chiefly from the underlying platform of greywackes and shales and from the Radiolarian cherts and volcanic rocks in the tableland to the south.
The culm measures already alluded to consist of black shales and slates with seams of grit and chert, much undulated through enormous lateral pressure.
Above the Ranikot beds are the massive nummulitic limestones and sandstones of the Kirthar group; these are succeeded by the nummulitic limestones and shales at the base of the Nari group.
Beneath the thick nummulitic Eocene limestone of the Salt Range are shales and marls with a few coal seams.
The beds above the limestone are shales and sandstones, sometimes reaching the true Coal-Measures, but rarely younger than the English Millstone Grit.
Its lower part represents the Lower Carboniferous Shales and Sandstones of the central and northern areas, while its upper part corresponds with a portion of the Carboniferous Limestone.
Along the eastern feet of the Shawangunk Mountains are Heidelberg limestones, gray and Medina sandstones, shales and grits, and the mountain rocks are mostly sandstones, shales and grits.
Soft shales were exposed in the gullies and on the sides of the hills, and were overlaid compact gray sandstones.
White sandstone and shales began to make their appearance on the banks, and the water in the river had a saline taste.
These sandstones are at least 200 feet thick, and rest on soft shales of white-brown and green colour.
Sometimes the limestones are degenerate or wholly deficient, and the series may consist of sandy shales and gypsiferous clays.
In other regions, however, it consists principally of shales and sandstones, with subordinate beds of limestone, and sometimes with this beds of coal or deposits of clay-ironstone.
The series is divided into a lower and upper group, the latter chiefly composed of shales and flags, and the former of sandstones and shales, together with the important and interesting calcareous band known as the "Bala Limestone.
The Upper Lias (Terrain Toarcien of D'Orbigny) attains a thickness of 300 feet, and consists principally of shales below, passing upwards into arenaceous strata.
This brings us up to the Tertiary Period, during the early part of which the pink limestones and shales of the Paleocene and Eocene Wasatch Formation were laid down in inland basins.
Green River, is missing from the Needles district, its place in the rock column being taken by red shales and sandstones of the Cutler Formation.
The rock is the Cedar Mesa Sandstone, which here underlies red shales beneath the White Rim Sandstone.
I and my companion William Shales came to Aleppo with the Carauan the eleuenth of Iune, 1584.
I and my companion William Shales hauing dispatched our businesse at Balsara, imbarked our selues in company of seuenty barks all laden with marchandise, hauing euery barke 14.
Contortions are also most commonly found in thin-bedded, flexible rocks, such as shales and schists.
Kerry includes on the north and east a considerable area of Carboniferous shales and sandstones, reaching the coal-measures, with unproductive coals, east of Listowel and on the Glanruddery Mountains.
Along the south-east the broken ground of Silurian shales forms the higher country, rising towards the Leinster chain.
South-east of this line graptolitic Silurian shales of Llandovery age prevail; they are found around Dalry, Creetown, New Galloway, Castle Douglas and Kirkcudbright.
The Ordovician rocks are graptolitic black shales and grits of Llandeilo and Caradoc age.
The upper Keuper, Rhaetic or Avicula contorta zone in Germany is mainly sandy with dark grey shales and marls; it is seldom more than 25 metres thick.
On the coast of the Maritime Alps Lyell had found huge beds of conglomerate, parted one from another by laminated shales full of fossils, most of which were identical with creatures still living in the Mediterranean.
Carvill Lewis believed the blue ground to be true eruptive rock, and the carbon to have been derived from the bituminous shales of which it contains fragments.
Here the sandstone will be found in contact with the trap above and the layers of basalt, trap, tufa, sandstone, shales and conglomerates are exposed.
They spent the day among its richly fossiliferous shales and limestones, and brought back with them in the evening, Ammonites and Gryphites enough to store a museum.
The ancient seas swarmed with these living hydrozoans, and their remains are found preserved as fossils in the shales which once were beds of soft mud.
The Connecticut River Valley, with its red sandstones and shales of the Mesozoic Era, is famous among geologists, because it preserves the tracks of reptiles, insects, and crustaceans.
Moreover, the veins of coal preserve above or below them, in shales that were once deposits of mud, the branching trunks of trees, perfectly fossilized.
The shales produce heavy, cold clays and the yellow subsoil produces soils of a light, hungry character so that the two should, if possible, be mixed together.
In the Lower Coal Measures of Yorkshire and Lancashire, Stopes and Watson (23) have shown that the shales forming the roof of the Upper Foot Coal were derived from drifted sediments of marine origin.
The shales in these formations are occasionally soft and friable and are then termed marls, but this name is misleading as they contain no appreciable proportion of finely divided calcium carbonate as do the true marls[8].
For many industrial purposes, particularly for the manufacture of refractory goods, the clays and shales of the Carboniferous System are highly important.
They may consist of a considerable variety of minerals or may be almost entirely composed of quartz, but with the possible exception of some shales of great hardness, they are undoubtedly not clay.
They thus appear to be quite distinct from the shales above them, both in origin and physical characters.
Brickmaking shales may be found in any of the older geological formations, though they occur chiefly in the Silurian, Permian, Carboniferous and Jurassic systems.
The purer shales of the Coal Measures burn to an agreeable cream or buff colour, the less pure ones and those of the other formations mentioned produce articles of a brick-red or blue-grey colour.
It is, however, necessary to use only those shaleswhich are naturally of fine texture, as mechanical grinding cannot effect a sufficient sub-division of the particles of some of the coarser shales.
The gorge by which Dingman's Creek comes out is deep and massive, the entrance being a narrow canyon cut down into the Marcellus shales which make the towering cliffs along the river.
These valleys, underlaid by the shales as bed-rocks, have been filled up with drift by the glacier from one hundred to seven hundred feet in depth, and they constitute the famous region of the Minisink.
When cemented into coherent rocks, these deposits becomeshales or limestones, sandstones, and conglomerates, respectively.
There remains only the argillaceous class of sediments, the shales and slates, and so soon as we examine the composition of these rocks we are struck by the remarkable resemblance to that of the class of igneous rocks.
Under this rotary churning the soft shales are torn out near the bottom and in succession the harder layers above until the capping is reached (Fig.
For these reasons shales and slates are the only rocks which are likely to be fused by relief from load through the formation of anticlinal arches within the earth’s zone of flow.
The Table Mountain Sandstone passes up conformably into a sequence of sandstones and shales (Bokkeveld Beds), well exposed in the Cold and Warm Bokkevelds.
The Bokkeveld beds are conformably succeeded by the sandstones, quartzites and shales of the Witteberg series.
Among the Griquatown series of quartzites, limestones andshales are numerous bands of jasper and large quantities of crocidolite (a fibrous amphibole); while at Blink Klip a curious breccia, over 200 ft.
Here as well as elsewhere the coal beds are interstratified with various kinds of sedimentary rocks, most commonly with shales and sandstones.
Thousands of tracks of long-extinct great reptiles occur in the sandstones and shales of the Connecticut Valley of Massachusetts.
Also occurs as scattering crystals in shales and clays, and in some veins.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "shales" in a variety of sentences. We hope that you will now be able to make sentences using this word.
