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 former consisting of chalk, as in England, and the latter of sandstones and limestones with Hippurites.
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.
The Liassic beds are often metamorphosed and the limestones contain garnet and wollastonite.
The Devonian dolomites, limestones and red sandstones cover immense tracts and appear on the surface over a much wider area.
The Permian limestones and marls occupy a strip in E.
Lower Cretaceous limestones and schists, with radiolarian cherts, are extensively developed; and in many parts of the island Upper Creta 1 See L.
Ceous limestones with Rudistes and Eocene beds with nummulites have been found.
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.
Deep. It is characterized by semi-crystalline limestones and blue and white sandy marls.
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.
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.
Pure limestones do not frequently take on schistose facies.
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.
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.
At Duba some limestones may belong to the Lower Cretaceous.
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.
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.
The geological sequence of events appears to have been the following: - After the deposition of the Eocene (or Oligocene) limestone - which reposes upon a floor of basalts and trachytes - basalts and basic tuffs were ejected, over which, during a period of very slow depression, orbitoidal limestones of Miocene age - which seem to make up the great mass of the island - were deposited; then elapsed a long period of rest, during which the atoll condition existed and the guano deposit was formed; from then down to the present time there has succeeded a series of sea-level subsidences, resulting in the formation of the terraces and the accummulation of the detritus now seen on the first inland cliff, the old submarine slope of the island.
In the Umzimkulu river and in the Tugela river below its junction with the Buffalo, metamorphic limestones are associated with schists, gneisses and granites.
The slates are interbedded with limestones containing fossil brachiopods, which have led to their determination as Silurian or Devonian; but L.
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.
At Marbat the granite is overlaid by sandstone, presumably the Nubian sandstone: this is followed by marls containing Cenomanian fossils; and these are overlaid by Upper Cretaceous limestones, upon which rest isolated patches of Alveolina limestone.
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.