Limestones Sentence Examples
The Liassic beds are often metamorphosed and the limestones contain garnet and wollastonite.
Pure limestones do not frequently take on schistose facies.
Architectural variety and solidity are favoured in the buildings of the city by a wealth of beautiful building stones of varied colours (limestones, sandstones, lavas, granites and marbles), in addition to which bricks and Roman tiles are employed.
The Mesozoic begins with a Triassic land period in the mainland of Australia; while the islands of the Australasian festoon contain the Triassic marine limestones, which fringe the whole of the Pacific. The Triassic beds are best known in New South Wales, where round Sydney they include a series of sandstones and shales.
The sea encroached far on the land from the Great Australian Bight and there formed the limestones of the Nullarbor Plains.Advertisement
The Devonian dolomites, limestones and red sandstones cover immense tracts and appear on the surface over a much wider area.
In the extreme north-east are found the oldest rocks in the state - lower Devonian (the New Scotland beds of New York) and, not so old, an extension of the Lower Carboniferous which underlies the Warrior coalfields of Alabama, and which consists of cherts, limestones, sandstones and shales, with a depth of 800 to 900 ft.
The latest Cretaceous is the Ripley formation, which lies west of the northern part of the last-named, and, about Scooba, in a small strip, the most southerly of the Cretaceous - it is composed of coarse sandstones, hard crystalline white limestones, clays, sands, phosphatic greensands, and darkcoloured, micaceous, glauconitic marls; its greatest thickness is about 280 ft.
The state contains deposits of iron, gypsum, marl, phosphate, lignite, ochre, glass-sand, tripoli, fuller's earth, limestones and sandstones; and there are small gas flows in the Yazoo Delta.
The high land in the west of the island and the somewhat less elevated region in the east are formed of Upper Tithonian and Lower Cretaceous limestones, the latter containing Rudistes.Advertisement
The Blue Grotto is in the Tithonian limestones; it shows indications of recent changes of level.
Volcanic rocks, locally called "Toadstone," are represented in the limestones by intrusive sills and flows of dolerite and by necks of agglomerate, notably near Tideswell, Millersdale and Matlock.
A series of black shales with nodular limestones, the Pendleside series, rests upon the Mountain Limestone on the east, south and north-west; much of the upper course of the Derwent has been cut through these soft beds.
The bones of Pleistocene mammals, the rhinoceros, mammoth, bison, hyaena, &c., have been found at numerous places, often in caves and fissures in the limestones, e.g.
Calc-schists are usually argillaceous limestones in which a large development of biotite or phlogopite has occasioned foliation.Advertisement
Abich (Sur la structure et la geologic du Daghestan, 1862), the successive folds of Jurassic limestones and slates, all nearly parallel to the Caucasus, which form lofty, narrow plateaus.
Such a rock is typically exemplified by a coarse-grained sandstone or conglomerate, while a limestone may be naturally porous, or, like the Trenton limestone of Ohio and Indiana, rendered so by its conversion into dolomite and the consequent production of cavities due to shrinkage - a change occurring only in the purer limestones.
In Palestine a limestone containing Carboniferous fossils is found in the midst of the sandstone series, and here the sandstone is immediately succeeded by limestones with Hippurites and other fossils belonging to the Upper Cretaceous.
Cretaceous limestones cover the greater part of Palestine and rocks of the same period form Mt Lebanon, the Casius Mons, &c., farther north.
The plains inland from Berbera, and the maritime margins between the coast and foot of the plateau, consist of limestones of Lower Oolitic age with Belemnites subhastatus.Advertisement
At Duba some limestones may belong to the Lower Cretaceous.
The southern part of Mainland, from Laxfirth Voe to Fitful Head a series of dark schists and slates, is found with subordinate limestones.
Fossiliferous Cretaceous limestones containing Rudistes have been found in several parts of the island (Santiago de los Banos, Santa Clara province, &c.).
At Esperanza and other places in the Santa Clara province, bituminous plant-bearing beds occur beneath the Tertiary limestones, and at Baracoa a Radiolarian earth occupies a similar position.
It is the Tertiary limestones which form the predominant feature in the geology of Cuba.Advertisement
The soil of the island is almost wholly of modern formation, mainly alluvial, with superficial limestones as another prominent feature.
Deep residual clay soils derived from underlying limestones, and coloured red or black according to the predominance of oxides of iron or vegetable detritus, characterize the plains.
Feilden notes as suggestive that, though the explorers have not met with this formation on the northern shores of Greenland, yet it was observed that a continuation of the direction of the known strike of the limestones of Feilden peninsula, carried over the polar area, passes through the neighbourhood of Spitsbergen, where the formation occurs, and contains certain species identical with those of the Grinnell Land rocks of this horizon.
Galena occurs in veins in the Cambrian clay-slate, accompanied by copper and iron pyrites, zinc-blende, quartz, calcspar, iron-spar, &c.; also in beds or nests within sandstones and rudimentary limestones, and in a great many other geological formations.
The flat summit is formed by a succession of limestones - all deposited in shallow water - from the Eocene (or Oligocene) up to recent deposits in the above-mentioned atoll with islands on its reef.
In the Umzimkulu river and in the Tugela river below its junction with the Buffalo, metamorphic limestones are associated with schists, gneisses and granites.
Peletan classes all these limestones as Triassic. Triassic beds of the Pacific coastal type occur in a band along the south-western coast.
In the case of limestones the carbon dioxide of the air in association with rain and dew eats into them and leads to their disintegration.
It is present in variable amounts in limestones of all kinds, although its white ness may there be masked by the presence of iron oxide and other coloured substances.
Permeability is practically identical with the speed at which percolation takes place; through clay it is slow, but increases in rapidity through marls, loams, limestones, chalks, coarse gravels and fine sands, reaching a maximum in soil saturated with moisture.
It includes chalky limestones, siliceous earths, red clay, and, at the top, a layer of mudstone composed mainly of volcanic dust.
The limestones contain Globigerina and other Foraminifera, the siliceous beds are made of Radiolaria, sponge spicules and diatoms, while the red clay closely resembles the red clay of the deepest parts of the oceans.
The Oceanic series is generally overlaid directly, and unconformably, by coral limestones; but at Bissex Hill, at the base of the coral limestones, and resting unconformably upon the Oceanic series, there is a Globigerina marl.
Jukes-Browne and Harrison ascribe the Scotland beds to the Eocene or Oligocene period, the Oceanic series to the Miocene, the Bissex Hill marls to the Pliocene, and the coral limestones partly to the Pliocene and partly to the Pleistocene.
Generally, however, the Cretaceous beds do not appear, and the greater part of southern Arabia seems to be formed of Alveolina and nummulite limestones of Tertiary age.
Lower Cretaceous rocks, consisting of thick limestones, shales and marls, occur in Central Tunisia.
Limestones and marls represent the stages Cenomanian to Upper Senonian.
Geology.'--The Eastern Cordillera., which, however, is but little known, appears to consist, as in Bolivia, chiefly of Palaeozoic rocks; the western ranges of the Andes are formed of Mesozoic beds, together with recent volcanic lavas and ashes; and the lower hills near the coast are composed of granite, syenite and other crystalline rocks, sometimes accompanied by limestones and sandstones, which are probably of Lower Cretaceous age, and often covered by marine Tertiary deposits.
Above Lima the western chain of the Andes is composed of porphyritic tuffs and massive limestones, while the longitudinal valley of the Oroya is hollowed in carbonaceous sandstones.
Farther north, in the department of Ancachs, the Mesozoic belt is composed chiefly of sandstones and shales, and the limestones which form so prominent a feature above Lirna seem to have disappeared.
The neighbourhood of Verona is especially rich in fine limestones and marbles of many different kinds, especially a close-grained creamcoloured marble and a rich mottled red marble, which are largely used, not only in Verona, but also in Venice and other cities of the province.
Carboniferous rocks are represented by mountain masses of Fusulina and other limestones.
Recent limestones are being produced in this way and also in some places by the precipitation of calcium carbonate by sodium or ammonium carbonate which has been carried into the sea or formed by organisms. The precipitated carbonate may agglomerate on mineral or organic grains which serve as nuclei, or it may form a sheet of hard deposit on the bottom as occurs in the Red Sea, off Florida, and round many coral islands in the Pacific. Only the sand and the finest-grained sediments of the shore zone are carried outwards over the continental shelf by the tides or by the reaction-currents along the bottom set up by on-shore winds.
Hydrocarbons, such as petroleum, bitumen, paraffin, &c., are also found occasionally in coal, but more generally in the associated sandstones and limestones of the Carboniferous formation.
The commencement of the Carboniferous period is marked by a mass of limestones known as the Carboniferous or Sequences Mountain Limestone,which contains a large assemblage of carbon- of marine fossils, and has a maximum thickness in iferous S.W.
The value of the product of limestones and dolomites in 1900 was $124,728; in 1902, $228,662; of sandstones and quartzites in 1900, $37,038; in 1902, $165,565; while the value of all stone produced in 1907 was $497,962, and in 1908, $ 6 59,574.
Limestones and sandstone are also profitably quarried, the value of the product in 1908 being $530,945 for limestone and $2337 for sandstone.
Cretaceous marls and limestones appear at intervals, extending in places to the edge of the upper plateau, and are extensively developed on the Makonde plateau.
In the district around Port Glasgow, on the south coast of the eastern peninsula, are the Boioro limestones, also of unknown age; they are lead-coloured, brecciated limestones with interbedded dolerites.
In Rossel Island (Roua or Arova) occur crystalline schistose and volcanic rocks, and in Misima (St Aignan) limestones and lavas in addition.
Geologically the region is made up of Carboniferous limestones, clay slates and sandstones, containing anthracite and coal; of Cretaceous marls, chalk, sandstone and greensands - chalk cliffs, in fact, accompany the Don for 200 m.; and of Miocene limestones and clays.
To these leached guanos and phosphatized limestones the name sombrerite has been given.
In 1892 the phosphates of Tennessee, derived from Ordovician limestones, came into the market.
The Wairoa series includes marine limestones characterized by Monotis salinaria, and the Otapira series is characterized by Spiriferina spatulata.
The Cretaceous system includes the Waipara series, a belt of chalky limestones with some phosphate beds at Clarendon in eastern Otago.
These Cretaceous limestones are interbedded with glauconitic greensands, as at Moeraki Point in eastern Otago.
Its north-east portion consists of Upper Silurian coral limestones (Llandovery division), containing a rich fossil fauna and representing a series of folds running north-northwest.
The western portion of Kotelnyi is built up of Middle Devonian limestones and slates, folded the same way, of which the fossil fauna is similar to that of the Urals.
The total value of all mineral products in 1902 was $6,769,104, of which $6,464,258 were represented by gold and silver, $110,789 by sandstones and quartzites and $86,605 by limestones and dolomites; in 1908 the total value was $8,528,234, which was an i increase of more than $3,500,000 over the value in 1907.
They are rarely metamorphosed to the point of recrystallization, though locally shales are altered to roofing slates, sandstones are indurated, limestones slightly marblized, and coals, originally bituminous, are changed to anthracite in northern Pennsylvania, and to graphite in Rhode Island.
Former tributaries have given place to others developed with reference to the distribution of more or less easily eroded strata, the present longitudinal valleys being determined by the out-crop of soft shales or soluble limestones, and the parallel ridges upheld by hard sandstones or schists.
Near Luang Prabang, just beyond the border, in French territory, limestones with Productus and Schwagerina, like the Productus limestone of the Indian Salt Range, have been found; also red clays and grauwacke with plants similar to those of the Raniganj beds; and violet clays with Dicynodon, supposed to be the equivalents of the Panche series of India.
Farther south, at VienTiane, the Mekong passes through a gorge cut in sandstone, arkose and schists with a similar strike; while at Lakhon there are steeply inclined limestones which strike north-west.
Above these, marine Rhaetic beds appear at intervals, notably near Lame, where they are succeeded by Lower Lias shales and limestones.
Grits, igneous rocks, ashbeds and limestones may and often do show cleavage.
Such veins often attain a thickness of several feet, and sometimes possess a columnar structure perpendicular to the enclosing walls; they are met with in the crystalline limestones and other Laurentian rocks of New York and Canada, in the gneisses of the Austrian Alps and the granulites of Ceylon.
The Maryland building stone, of which there is an abundance of good quality, consists chiefly of granites, limestones, slate, marble and sandstones, the greater part of which is quarried in the east section of the Piedmont Plateau especially in Cecil county, though some limestones, including those from which hydraulic cement is manufactured, and some sandstones are obtained from the western part of the Piedmont Plateau and the east section of the Appalachian region; the value of stone quarried in the state in 1907 was $1,439,355, of which $1,183,753 was the value of granite, $142,825 that of limestone, $98,918 that of marble, and $13,859 that of sandstone.
They consist of gneiss, mica-schist, quartzites, crystalline limestones and conglomerates.
Rhaetic beds (Infra Lias), consisting of dolomites and siliceous limestones, have been recognized at Saida.
They are found on the borders of Guatemala and consist of limestones and dolomites with Productus.
The Jurassic beds are marls, sandstones and limestones, which contain marine fossils.
Galena is of wide distribution, and occurs usually in metalliferous veins traversing crystalline rocks, clay-slates and limestones, and also as pockets in limestones.
They are usually fine-textured limestones and shales, lying horizontal; the moderate or small relief that they were given by mature preglacial erosion is now buried under the drift, but is known by numerous borings for oil, gas and water.
Many small lakes in the lowland appear to owe their basins to the solution of the limestones.
This interior plain of the continent represents the area of the ancient sea by which it was occupied in Mesozoic times, with a more ancient margin towards the north-west against the Archean, where undisturbed limestones and other rocks of the Silurian and Devonian rest upon the downward slope of the Laurentian Shield.
The islands of these outer arcs consist chiefly of crystalline schists and limestones, overlaid by Jurassic, Cretaceous and Tertiary deposits.
Limestones and dolomites suitable for building purposes are obtained chiefly in Montgomery, Chester and Lancaster counties, and even these are generally rejected for ornamental work on account of their colour, which is usually bluish, grey or mottled.
They appear in some cases to be altered limestones and in others altered glauconitic sandstones.
These rocks were originally referred to the Carboniferous system, and similar limestones have been recorded in many parts of the island.
This genus is especially abundant in Eocene Limestones, which attain great thickness around the Mediterranean basin; the Pyramids of Egypt are built of it.
Eocene beds, indeed, penetrate farther within the chain, but these are limestones with nummulites or lignite-bearing shales and have nothing in common with the Flysch.
It is believed that the bluish colour of many clays and limestones is referable to the presence of finely divided pyrites, and it is known that certain deposits of blue mud now forming around continental shores owe their colour, in part, to disseminated iron sulphide.
Conybeare in 1821 to the coal-bearing strata of England and Wales, including the related grits and limestones immediately beneath them.
The stratified rocks of this system include marine limestones, shales and sandstones; estuarine, lagoonal and fresh-water shales, sandstones and marls with beds of coal, oil-bearing rocks, gypsum and salt.
This comprised dark shales, with grits and thin limestones and thin, impure coals, locally called " culm " (q.v.).
The so-called " unproductive " or barren strata, that is, those without workable coals, are not always limestones; quite as often they are shales, red sandstones and red marls.
The great variety of conditions under which the sediments and limestones were formed naturally produced corresponding inequalities in the thickness.
In western Europe the advent of the Carboniferous period was accompanied by the production of a series of synclines which permitted the formation of organic limestones, free from the sediments which generally characterized the concluding phases of the preceding Devonian deposition.
Thus western Europe in early Carboniferous time was occupied by a series of constricted, gulf-like seas; and on account of the steady progress of intermittent warping movements of the crust, we find that the areas of clearer water, in which the limestone-building organisms could exist, were repeatedly able to spread, thus forming those thin limestones found interbedded with shale and sandstone which occur typically in the Yoredale district of Yorkshire and in the region to the north, and also in the culm deposits of central Europe.
The spread of these limestones was repeatedly checked by the steady influx of detritus from the land during the pauses in movements of depression.
The sea had gained somewhat at the beginning of the Carboniferous period in western Europe, but the effect of these movements, combined with the rapid formation of detrital deposits from the rising land areas, was to drive the sea steadily from the north towards the south, until the open sea (with limestones) was relegated to what is now the Mediterranean and to Russia and thence eastward.
The beds of chert are utilized in the pottery industry, and some of the harder and more crystalline limestones are beautiful marbles, capable of taking a high polish.
They consist of breccias, conglomerates, sandstones, marls, and limestones, with seams of coal and lignite.
Blende occurs in metalliferous veins, often in association with galena, also with chalcopyrite, barytes, fluorspar, &c. In oredeposits containing both lead and zinc, such as those filling cavities in the limestones of the north of England and of Missouri, the galena is usually found in the upper part of the deposit, the blende not being reached until the deeper parts are worked.
This forms part of the plain of the St Lawrence, underlain by Palaeozoic limestones and shales, with some sandstone, all furnishing useful building material and working up into a good soil.
The south-western part is naturally divided into two tracts by the Niagara escarpment, a line of cliffs capped by hard Silurian limestones, running from Queenston Heights near the falls of Niagara west to the head of Lake Ontario near Hamilton, and then northwest to the Bruce Peninsula on Georgian Bay.
The limestones of which they are mostly composed act like a sponge, absorbing the rain-water through their innumerable pores and fissures, and thus storing it up in the interior, afterwards to allow it to well forth in springs at various elevations lower down.
Limestones, with fossils indicating a Tertiary age, have been found near Sokoto.
They are conformably overlain by clays and limestones with Exogyra Overwegi belonging to the Lower Danian, and these by clays and white chalk with Ananchytes ovata of the Upper Danian.
The materials are quartz crystal, basalt, porphyry, syenite, granite, volcanic ash, various metamorphics, serpentine, slate, dolomite marble, alabaster, many colored marbles, saccharine marble, grey and white limestones.
These are still largely used, and are prepared by burning limestones containing clayey matter.
Ordinary mortar failed in such positions; mortar made from lime prepared from limestones or chalks containing a little clay was found to stand; mortar made from lime mixed with trass or similar active silicious material was also found to stand.
Crystalline rocks crop out at several capes; Cretaceous limestones, containing an abundant and specific fauna of gigantic ammonites, occur at Dui on the west coast, and Tertiary conglomerates, sandstones, marls and clays, folded by subsequent upheavals, in many parts of the island.
Traces of annelids have been detected in some of the quartzites, and some of the less changed parts of the limestones may be searched for fossils.
And to the soil created by the decay of the limestones is due a greener verdure than that of the surrounding moors.
Rocks of Cambrian age have not been identified elsewhere in Scotland, though it may ultimately be shown that the quartzites and limestones of the Central Highlands are equivalents of those of the north-west coast.
The Jurassic system - comprising, in descending order, the subdivisions of Upper Oolites (Portlandian Kimmeridge Clay), Middle Oolites (coal limestones; Oxford clay), Lower Oolites (Great Oolite series; Inferior Oolite series), Lias (Upper, Middle, Lower) - is well represented on both sides of the Highlands.
The Middle Oolite consists mostly of sandstones with bands of shale and limestones, and includes fossils which indicate the English horizons from the Kellaways Rock up to the Coral Rag.
The Lower, Middle and Upper Lias consist chiefly of shales and shelly limestones, with some sandstones, well seen along the shores of Broadford Bay in Skye and in some of the adjacent islands.
The Lower Oolites are made up of sandstones and shales with some limestones, and are overlaid by several hundred feet of an estuarine series of deposits consisting chiefly of thick white sandstones, below and above which lie shales and shelly limestones.
Fars series; marls, clays and sand stones with limestones and inter bedded strata of rock gypsum.
These are overlaid conformably by a thick series of platy limestones, known as the Viglas limestone, which appears to represent the rest of the Jurassic system and also the lower part of the Cretaceous.
Then follows a mass of dolomite and unbedded limestones containing Hippurites and evidently of Upper Cretaceous age.
The Upper Cretaceous is represented by limestones with bands of chert, and contains Ammonites, Baculites, Hippurites and other fossils.
It is overlaid towards the west by similar limestones, which contain nummulites and belong to the Eocene period; and these are followed near the coast by the calcareous sandstone of Philistia, which is referred by Hull to the Upper Eocene.
Through these, again, pierce other granites in dikes or lava flows, and overlying the whole are limestones of Cretaceous and Tertiary age, themselves cut through by later volcanic eruptions.
The Vindhyans are well-stratified beds of sandstone and shale, with some limestones.
Coral limestones, probably of Middle Tertiary age, are also found, sometimes 4000 ft.
The lower limestones are well seen at Corrie, but the thin coals are not there represented.
The Triassic rocks are arranged in two groups, a lower, composed of conglomerates and sandstones, and an upper one consisting of red and mottled shales and marls with thin sandstones and nodular limestones.
The geology of Borneo is very imperfectly known The mountain range which lies between Sarawak and the Dutch possessions, and may be looked upon as the backbone of the island, consists chiefly of crystalline schists, together with slates, sandstones and limestones.
The Tertiary system includes conglomerates, sandstones, limestones and marls, which appear to be of Eocene, Oligocene and Miocene age.
In Scotland, North America and Canada important deposits of limestone occur and subordinate limestones are found in the Cambrian of central Europe.
Thus, we find them more frequently, folded, tilted and cleaved; the muds have become shales, slates, phyllites or schists, the grey and red sands and conglomerates have become quartzites and greywackes, while the limestones are very generally dolomitized.
In the Cambrian limestones, as in their more recent analogues, layers and nodules of chert and phosphatized material are not wanting.
In the Rennes basin limestones - often dolomitic - are associated with quartzites and conglomerates; silicious limestones also occur in the Sarthe region.
Limestones of Eocene or Cretaceous age form a large part of the Taurus, but the interior zone probably includes rocks of earlier periods.
Cretaceous limestones and serpentine take a large part in the formation of these mountains, while even the Oligocene is involved in the folds.
The greater elevations are for the most part formed of limestones, except in the south, where they are largely volcanic. The coasts of the Gulf of Akaba are steep, with numerous coral reefs on both sides.
The northern coast range is formed by the oldest rocks in the island, consisting chiefly of limestones and marbles with occasional masses of igneous rock.
It was entirely covered with the bottom moraine of the great ice-sheet of the Glacial Epoch, resting upon Silurian sandstones and limestones.
With these are often associated limestones, dolomites and marbles containing serpentine (Kolmarden).
The upper divisions consist of bituminous limestones, clay-slates, alum-slate, and contain numerous species of trilobites of the genera Paradoxides, Conocoryphe, Agnostus, Sphaerophthalmus, Peltura, &c. The Ordovician formation occurs in two distinct facies - the one shaley and containing graptolites; the other calcareous, with brachiopods, trilobites, &c. The most constant of the calcareous divisions is the Orthoceras limestone, a red or grey limestone with Megalaspis and Orthoceras.
The Silurian has in Sweden almost the same character as the Wenlock and Ludlow formation of England and consists partly of graptolite shales, partly of limestones and sandstones.
The deposits are marls, sandstones and limestones, and were evidently formed near the shore-line.
Towards the north these are associated with fresh-water limestones, indicating the presence of land in that direction.
Besides limestones and dolomites, the only building stone of much commercial importance is the Potsdam sandstone, extensive beds of which lie in the north part of the upper peninsula.
The typical Silurian rocks are richly fossiliferous, the shales containing trilobites, the sandstones many brachiopods, and the limestones a rich coral and bryozoan fauna.
Caves have been dissolved in the limestones by underground streams; the Jenolan caves in the Blue Mountains and those of Yarrangobilly and the Goulburn district are the most famous.
Some schists, attributed to the Silurian, but possibly older, contain platinum; and associated with the limestones are beds of copper.
The Lower Carboniferous beds are represented by conglomerates and sandstones with some shales and limestones.
Where the Coal Measures reach the sea at Whitehaven, there are coal-mines, and the hematite of the Carboniferous Limestones has given rise to the active ironworks of Barrow-in-Furness, now the largest town in the district.
The belt of Millstone Grit south of the Aire, lying between the great coal-fields of the West Riding and Lancashire, has a lower elevation, and forms grassy uplands and dales; but farther south, the finest scenery of the whole region occurs in the limestones of Derbyshire, in which the range terminates.
Each group is made up of an alternation of soft marls or clays and hard limestones or sandstones.
There are very few dwellings situated at a higher level than moo ft., and on the lower ground the Chalk and the Oolitic limestones, where they crop out on the surface, are extremely thinly peopled, and so as a rule are areas of alluvial deposits and the Tertiary sands.
Closely following the same line are the alternating clays and limestones of the Oolitic series.
They are overlain by the fossiliferous limestones of the Antalo group. Around Chelga and Adigrat coal-bearing beds occur, which Blanford suggests may be of the same age as the coalbearing strata of India.
The fossiliferous limestones of Antalo are generally horizontal, but are in places much disturbed when interstratified with trap rocks.
Their relation to the Antalo limestones is uncertain, but Blanford considers them to be not later in age than the Oolite.
In limestones of various kinds it occurs as nodules and bands of chert and flint, being in this case of organic origin.
At Ampthill a development of clay, the Ampthill clay, represents the Corallian limestones of neighbouring counties.
The Great Ouse, from the point where it enters the county on the west, has carved through the Middle Oolites and exposed the Great Oolite as far as Bedford; their alternating limestones and clays may be seen in the quarries not far from the town.
Superficially, each is a simple rolling plateau, much broken by erosion (though considerable undissected areas drained by underground channels remain), especially in the east, and dotted with hills; some of these are residual outliers of the eroded Mississippian limestones to the west, and others are the summits of an archaean topography above which sedimentary formations that now constitute the valley-floor about them were deposited and then eroded.
Limestones are by far the most important; red and gray granites, sandstones and marble (Ste Genevieve county) being of little more than local importance.
These are overlaid by sandstones, slates and limestones, alternating with porphyries and porphyrites, sometimes in the form of sheets, sometimes as breccias and conglomerates.
The chief rocks of the Campbell Rand series are limestones and dolomites, with some interbedded quartzites.
Among the Griquatown series of quartzites, limestones and shales are numerous bands of jasper and large quantities of crocidolite (a fibrous amphibole); while at Blink Klip a curious breccia, over 200 ft.
Perennial springs of large volume rarely occur in Great Britain at a sufficient height to afford supplies by gravitation; but from the limestones of Italy and many other parts of the world very considerable volumes issue far above the sea-level, and are thus available, without pumping, for the supply of distant towns.
The so-called "Limestones" of the Derbyshire hills are really Leicesters.
There are marbles in Osage and other counties, shell marble in Montgomery county, white limestone in Chase county, a valuable bandera flagstone and hydraulic cement rock near Fort Scott, &c. The limestones produced in 1908 were valued at $403,176 and the sandstones at $67,950.
Slates, schists, quartzites and limestones form the greater part of the hills, but the Brocken and Victorshohe are masses of intrusive granite, and diabases and diabase tuffs are interstratified with the sedimentary deposits.
In the south the deposits, from the Trias to the middle Eocene, consist mainly of limestones, and were laid down, with a few slight interruptions, upon a quietly subsiding sea-floor.
Beyond this belt there appear in the north-west Mesozoic limestones, such as occupy so extensive an area in the north-west of the Balkan Peninsula generally, and the valleys opening in that quarter to the Drina have the same desolate aspect as belongs to these rocks in the rest of that region.
The Alai is a well-defined ridge with steep slopes, and both it and the Terek-tau, which prolongs it towards the Kokshal-tau, are flanked next the Ferghana valley by what appear to be the old uplifted strata both of the old Palaeozoic series of metamorphic limestones and of the newer Tertiary series of softer conglomerates and sandstones.
In some places limestones appear as projections from the range; at others conglomerates and Tertiary clay marls form the outermost fold."' On the north versant of the ranges the rainfall increases from the foot of the mountains upwards, and at woo-10,000 ft.
The oldest rocks in this large area are a stratified series of mica-schists, limestones and quartzites, with numerous intrusive sheets of diorite, the whole having been metamorphosed by pressure, with frequent overfolding.
Near the latter locality, beds of Oligocene age have been noticed, consisting of coarse limestones.
The Lower Carboniferous rocks of Spain consist partly of limestones, and partly of shales, sandstones and conglomerates like the culin of Devonshire.
The Upper Carboniferous is formed to a large extent of sandstones and shales, with seams of coal; but beds of massiye limestones are often intercalated, and some of these contain Fusaljna and other fossils like those of the Russian Ftisulina limestone.
The higher members comprise massive hippurite limestones, and in the Pyrenean district representatives of the upper subdivisions of the system, including the Danian.
The marine Tertiary accumulations commence with those that are referable to the Eocene series, consisting of nummulitic limestones, marls and siliceous sandstones.
Of building stones limestones are the most abundant and important, the best comes from the Benton beds and when " green " can be sawed into blocks.
The rocks are best known by the limestones in the lead mining field at Zeehan, and the slates, including the tin mine of Mount Bischoff.
The Carboniferous system begins with a series of marine limestones, shales and grits, including a rich Lower Carboniferous fauna.
The calcareous Siphoneae are represented by several forms, identified as species of Diplopora, Triploporella, Neomeris and other genera, from strata ranging from the lower Trias limestones of Tirol to the Cretaceous rocks of Mexico and elsewhere.
A genus Zonatrichites, compared with species of Cyanophyceae, has been described as a Calcareous alga from Liassic limestones of Silesia.
As the impurities increase in amount the clay rocks pass gradually into argillaceous sands and sandstones, argillaceous limestones and dolomites, shaly coals and clay ironstones.
It consists of parallel ridges and valleys developed by erosion on folded sandstones, shales and limestones, the valley quality predominating because the weak limestones were of great thickness.
These are overlaid by conglomerates, limestones and clay slates of very doubtful age, the most interesting being a radiolarian clay which occurs on the south side of the Matinang Mountains, at the north end of Lake Posso, &c.; it may correspond with the radiolarian cherts of Borneo.
The Eocene includes a series of sandstones and marls with lignite, and these are overlaid by nummulite limestones.
Dalradian limestones commonly have Sr greater than 1000 ppm, indicating primary aragonite and marine diagenesis.
In the Middle Devonian deeper water conditions have produced mudstones, thin limestones and slates which rarely yield fossils.
In general, Tertiary basalts rest unconformably and in faulted contact with cretaceous greensands and limestones or dark gray, fossil-bearing Jurassic mudstones.
Above the basal greensand occur the limestones of the Ulster White Limestone Group.
In general, Cretaceous greensands and limestones or Tertiary basalts rest unconformably on a range of older Mesozoic rock units.
South of the Clougher Valley the carboniferous limestones have sandstone deposited on top with beds of shale contained in the sandstones.
The eastern part has no chalk capping and is subject to frequent mudslides in the waterlogged soft limestones and clays.
The Waterloo mudstone Formation spans the Triassic Jurassic boundary, and comprises dark gray mudstones and shales, alternating with gray limestones.
In Russia and South Africa, gently deposited mudstones and limestones suddenly give way to massive dumps of pebbles and boulders.
The calcareous mudstones and limestones are rich in fossils.
These dark gray mudstones, gray to black shales and minor limestones contain ammonite and rare reptile fossils.
In past geological eras, various rocks including quartzite, grits and the Durness limestones were laid over much of the area.
Here, although exposures are very poor, the Silurian rocks comprise shales, sandstones and limestones with a couple of beds of lava.
The Middle Devonian was marked by the same great transgression as in Europe and America; it produced inland seas, extending into Victoria, New South Wales and Queensland, in which were deposited limestones with a rich coral fauna.
The Carboniferous period began with a marine transgression, enabling limestones to form in Tasmania and New South Wales; and at the same time the sea first got in along the western edge of the western plateau, depositing the Carboniferous rocks of the Gascoyne basin and the coastal plain of north-western Australia.
The sedimentary schists or paraschists have three great subdivisions, the mica-schists and chlorite-schists (which correspond in a general way to shales or clay rocks) the calc-schists (impure limestones) and the quartz-schists (metamorphosed sandstones).
The lower and middle divisions of the Jurassic, composed of massive limestones more or less siliceous and overlain by the marls amd highly fossiliferous limestones of the Upper Lias, play an important part in the constitution of the chief mountains of the Tell.
Between the "Cotton Belt" and the Tennessee Valley is the mineral region, the "Old Land" area - "a region of resistant rocks" - whose soils, also derived from weathering in situ, are of varied fertility, the best coming from the granites, sandstones and limestones, the poorest from the gneisses, schists and slates.
Traced eastward into north Germany, Thuringia and Silesia, the limestones pass into the detrital culm formations, which owe their existence to a southern uplifted massif, the complement of the synclines already mentioned.
Tertiary limestones, sandstones and shales overlie the Deccan Trap in Cutch, but the greatest development of deposits of this age is to be met with on the western side of the Indus (see Sind).
This weathering feature of hard limestones arises through the gradual dissolution of the limestone by rainwater, which is slightly acidic.
Stay away from white colored stones, since these can discolor easily, and watch out for very soft limestones, such as Lagos Azul, which can pit inside a shower.
While limestone is not generally recommended for countertops because of its soft makeup, French limestones are actually both hard enough and dense enough to handle being used on a kitchen counter.