Greensand sentence example
Amber and certain similar substances are found to a limited extent at several localities in the United States, as in the greensand of New Jersey, but they have little or no economic value.
The Cambridgeshire coprolites are either amorphous or finger-shaped; the coprolites from the Greensand are of a black or dark-brown colour; while those from the Gault are greenish-white on the surface, brownish-black internally.
They are found in the Lower Greensand, or Upper Neocomian series, in the Atherfield Clay at Stopham, near Pulborough; occasionally at the junction of the Hythe and Sandgate beds; and in the Folkeston beds, at Farnham.
But in 1858 were discerned in the Upper Greensand of Cambridgeshire remains which are now known as Enaliornis.
The Maltese Islands consist largely of Tertiary Limestone, with somewhat variable beds of Crystalline Sandstone, Greensand and Marl or Blue Clay.Advertisement
The actual coal measure strata, consisting mainly of shales and clays, are generally impervious to water, but when strata of a permeable character are sunk through, such as the magnesian limestone of the north of England, the Permian sandstones of the central counties, or the chalk and greensand in the north of France and Westphalia, special methods are required in order to pass the water-bearing beds, and to protect the shaft and workings from the influx of water subsequently.
Mantell in the Wealden formation of Sussex, and a large part of the skeleton, lacking the head, was subsequently discovered in a block of ragstone in the Lower Greensand near i Skeleton of Iguanodon bernissartensis.
Bands of black nodules, highly phosphatic, are found at the top of the Bala limestone in North Wales; beds of concretions occur in the Jurassic series; and important deposits are known in the Cretaceous strata, especially in the Lower Greensand and at the base of the Gault.
The Lower Greensand phosphates have been worked, under the name of " coprolites," at Potton in Bedfordshire and at Upware and Wicken in Cambridgeshire.
The Cambridge Greensand, rich in phosphatic nodules, occurs at the base of the Chalk Marl.Advertisement
Below the chalk is a thin crop of Upper Greensand between Otford and Westerham.
This is succeeded by an outcrop of the Lower Greensand - including the Folkestone, Sandgate and Hythe beds with the thin Atherfield Clay at the base - which extends across the country from west to east with a breadth of from 2 to 7 m., and rises into the picturesque elevations of the Ragstone hills.
Lime is obtained from the Chalk and Greensand formations.
The most distinctive feature of the Cretaceous of the Atlantic coastal plain is its large content of greensand marl (glauconite).
Deposits of brown iron ore of great economic value occur in many sedimentary rocks, such as the Lias, Oolites and Lower Greensand of various parts of England.Advertisement
Some greenish sandstones containing recognizable and characteristic fossils are the equivalents of the Upper Greensand of the south of England.
The mining of natural fertilizers - white and greensand marls - is a long established industry; the output in 1907 was 14,091 tons, valued at $8429.
Within the Chalk ring, and at the base of the steep escarpment, there is a low terrace of the Upper Greensand, seldom so much as a mile in width, but in most places crowded with villages scarcely more than a mile apart, and ranged like beads on a necklace.
Within the Upper Greensand an equally narrow ring of Gault is exposed, its stiff clay forming level plains of grazing pasture, without villages, and with few farmhouses even; and from beneath it the successivOeds of the Lower Greensand rise towards the centre, forming a wider belt, and reaching a considerable height before breaking off in a fine escarpment, the crest of which is in several points higher than the outer ring of Chalk.
The Lower Greensand escarpment looks inwards in its turn over the wide plain of Weald Clay, along which the Medway flows in the north, and which forms a fertile soil, well cultivated, and particularly rich in hops and wheat.Advertisement
From Woburn through Ampthill to Potton a more elevated tract is formed by the Lower Greensand.
Above the Lower Greensand comes the Gault Clay, which lies in the broad vale south-east of the former and north-west of the Chalk hills.
In the New Red Sandstone, the Greensand and the upper Chalk, we find the opposite extremes; while the igneous rocks are for the most part only permeable in virtue of the open fissures they contain.
Where the strata are not uniformly porous, they may resist the passage of water from the direction of the sea or they may assist it; and round the whole coast of England, in the Magnesian limestone to the northeast, in the Chalk and Greensand to the east and south, and in the New Red Sandstone to the west, the number of wells which have been abandoned as sources of potable supply, owing to the percolation of sea water, is very great.
Brownish cherts are found in the English Greensand; these often contain remains of sponges.Advertisement
These two stages represent the Upper Greensand, or the sandy type of the English Gault.
In the Cretaceous system of the Wolds, the Lower Greensand runs nearly parallel with the Upper Oolite past South Willingham to the Humber.
The Upper Greensand and Gault, represented in Lincolnshire by the Red Chalk, run north-west from Irby, widening out as far as Kelstern on the east, and cross the Humber.
The best preserved specimens of the true Bennettites type so far described are from the Lower Greensand and Wealden of England, and from Upper Mesozoic strata in North America, Italy and France.
Fossil wood of the Pinites type (Pityoxylon) has been described from England, France, Germany, Sweden, Spitsbergen, North America and elsewhere; some of the best British examples have been obtained from the so-called Pine-raft, the remains of water-logged and petrified wood of Lower Greensand age, seen at low water near Brook Point in the Isle of Wight.Advertisement
In rocks approximately equivalent to the Lower Greensand of England, or slightly earlier, Angiosperms make their first appearance; but as the only strata of this age in Britain are of marine origin, we have to turn to other countries for the evidence.
The workings occur all along the base of the downs, where the narrow strip of upper greensand joins the chalk.
The area we visited was on the boundary of the chalk and lower greensand where the harder rocks of the upper greensand are exposed.
Above the basal greensand occur the limestones of the Ulster White Limestone Group.
The term " Hibernian Greensand " was used by Tate for all the beds below the Senonian; the quarrymen know the conglomeratic Senonian as " Mulatto-stone."Advertisement
Ironstone within a small outcrop of the Lower Greensand at Seend was formerly quarried and the ore smelted on the spot.
Greensand is a mineral that contains an iron-potassium silicate known as glauconite.
Greensand is especially helpful when you are dealing with a heavy clay soil.