Chalk pit

“ CHALK is a white or yellowish kind of limestone, too well known to need any description.
It is found abundantly in many of the southern counties of England, and is usually procured from large open places, called chalk-pits, by digging. In some parts of Kent, however, the workmen save themselves, in this respect, much trouble. They undermine the sides of hills to a certain depth, then dig a trench at the top as far distant from the edge as the mining extends at the bottom. ”

“ Fig. 35.—“Chalk weight, 6" × 4" × 2" (15·2 cm. × 10·2 × 5·1) , similar to those found in pits, at Mount Caburn and Cissbury near Worthing, Sussex. Found with eighteen more in the filling of pit 7, Winkelbury Hill.” Excavations in Winkelbury Camp, by Lieut.-Gen. Pitt-Rivers (Excavations in Cranbourne Chase, Vol. II., 1888) . As Pitt-Rivers also found at Winkelbury the fragment of a comb and a chalk spindle whorl, which are textile tools, we may safely presume these fashioned pieces of chalk are warp weights. ”

“ A little farther west, on the north side of the turnpike, is another gravel-pit, showing a similar succession, but with the beds of sand and gravel strongly false-bedded. In all these sections small pebbles of chalk are very abundant in the lowest beds. The most remarkable feature in the upper bowlder-clay is the numerous angular patches of material quite different from the matrix of brown clay. The angular patches of red sand are very peculiar and difficult to explain. ”

“ Like slate, chalk comes out of the hills. It is white and soft. It is used for many purposes. The farmer puts it on the fields sometimes, to make the soil better. It holds water and keeps the soil moist.
2. We get lime and whiting from chalk. We use it in these forms for making our ceilings and walls clean. It is used, too, for writing on the blackboard. Chalk is found in many parts of England. Kent and Hampshire have most. Chalk-pits are often seen in the hills. ”

“ Holmes remarks,2440 ‘it must be obvious that the course which would commend itself to all seekers after superior chalk would be to begin operations where chalk is at the surface, 517 make a shaft 10 to 20 feet deep, and procure chalk lying at that depth’; and, while he freely admits that ‘a farmer might naturally prefer to get chalk at a depth of 60 to 80 feet on his own land rather than ... from some one else’s pit a mile or two away’, he emphasizes the absurdity of supposing that ‘any people ... ”

“ In tracing this vast collection of water-worn materials, we find that it forms a considerable hill behind the town, and that it joins to the side of the range of hills called the South Downs.
In Alum bay in the Isle of Wight, however, the stratum immediately next to the flinty chalk, and consequently deposited upon it, consists of a white chalk marl without flints. Its nature is sufficiently shewn by its pulverizing with the frost; and the rains wash it down, so that its situation is marked by a deep hollow. ”

“ But the chalk stands up to right and left in noble cliffs, of which Haven Ball forms the eastern jamb, and White Cliff that to the west. From Haven Ball the coast forms one continuous white precipice to Lyme Regis, above a sea in summer of peacock blue.
But, as every tyro in geology knows, the chalk is built up over the green sand, below which are impervious beds of clay. The rain soaking down through the faults in the chalk reaches the argillaceous stratum, and, unable to descend farther, forms innumerable land springs such as come forth at the base of most chalk hills. ”

“ The White Cliff is composed of a cap of chalk, a hundred feet thick, striated with beds of flint, and this rests on a series of shelving cherty sandstone beds of a tawny hue. The inclination of these gives to the whole headland an appearance of lurching to its fall.
Water sinking through the chalk oozes through the sand and dissolves it, undermining the white bed above till masses of chalk that have lost all support hurtle down. But the chalk itself is full of cavosities caused by the soft rock being eaten into by the sea-winds. ”

“ The Chalk is everywhere very thinly peopled, except where it is thickly covered with boulder clay, and so becomes fertile, or where it is scored by drift-filled valleys, in which the small towns and villages are dotted along the high roads. The thickest covering of drift is found in the Holderness district of Yorkshire, where, from the chalk cliffs of Flamborough Head to the sandspit of Spurn Point, the whole coast is formed of boulder-clay resting on chalk. ”

“ Composition and Uses.—In the Andover district Chalk Compost or “Chalk Mud,” as it is called locally, is prepared and used as follows:
The chalk is dug out in the autumn, and the frost allowed to play on it during the winter. In the spring building starts, and the weathered chalk is spread all around the outside of the walls. Straw is sprinkled on it and it is then well trodden, usually by the workers, but sometimes by horses. Sometimes chopped straw is added, sometimes unchopped straw is sprinkled on. ”

“ Its representatives in eastern France, in the north zone of the Alps, or in the central Apennines, are compressed into far more resisting masses, and rear themselves as terraced crags and sheer rock-walls, in which the structure due to vertical joints is paramount. The English Chalk weathers into round-backed downs, clothed with thin grass, and hollowed into combes by streams that have long ago run dry. The soil owes hardly anything but its abundant flints to the white limestone rock on which it lies. ”

“ The several beds of these chalk strata, which vary in thickness from a few inches to several feet, are frequently separated from each other not only by layers of flint nodules but frequently also by a marl containing a considerable proportion of clay, and this substance also sometimes fills up the diagonal fissures which cross the strata. The workmen take advantage of this circumstance in quarrying the chalk. ”

“ In a chalk country, such as that through which the Somme flows, each cubic foot of flint, gravel or sand, represents the removal of at the very least twenty cubic feet of chalk, all of which, as we have already seen, must have been removed from the present area of drainage. In considering, therefore, the formation of these upper and older gravels, we must not picture to ourselves the original valley as it now is, but must, in imagination, restore all that immense mass of chalk which has been destroyed in the formation of the lower level gravels and sands. ”

“ There is a stiff loam, in some places twenty feet deep, on a bottom of chalk. Though the grass grows so finely, there is no apparent wetness in the land. The wells are more than three hundred feet deep. The main part of the water, for all uses, comes from the clouds; and, indeed, these are pretty constant companions of these chalk hills, which are very often enveloped in clouds and wet, when it is sunshine down at Burghclere or Uphusband. They manure the land here by digging wells in the fields, and bringing up the chalk, which they spread about on the land ”

“ To a thinking mind few phenomena are more strange than the state of little ponds on the summits of chalk hills, many of which are never dry in the most trying droughts of summer. On chalk-hills I say, because in many rocky and gravelly soils springs usually break out pretty high on the sides of elevated grounds and mountains: but no person acquainted with chalk districts will allow that they ever saw springs in such a soil but in valleys and bottoms, since the waters of so pervious a stratum as chalk all lie on one dead level, as well-diggers have assured me again and again. ”

“ The ornamental chimney-stacks were put in for the sake of appearance, flues built up in the chalk being entirely satisfactory and fireproof. The foundations are either flint or brick with a slate damp-course.
“I consider that for a chalk country this method of building has many advantages.
“ (1) It saves cartage.
“ (2) It can be carried out by a skilled labourer who can be otherwise employed during unsuitable weather.
“ (3) No fuel is required as in burning bricks. ”

“ The hard chalk lies immediately beneath the soft chalk. In this stratum there are no flint nodules. “ Its beds,” according to Mr. Farey, “ increase in hardness, until near the bottom where a whitish freestone is dug, at Totternboe in Bedfordshire, and at numerous other places; that brought from Ryegate and other quarries, of this stratum, south of London, is used as a fire-stone.” [11]
It has been generally supposed that these two strata of chalk are of one formation: but not only the absence of the flints, but the characters of their fossils prove them to be of distinct formations. ”

“ The chalk formation which stretches across England from Hampshire to Yorkshire, makes its appearance here as a thin white band under the clay, becoming thicker and thicker, till at length the whole cliff is chalk from base to summit, and the great promontory, of snowy whiteness, gleams afar in the sunlight along the shores and across the sea. The chalk opposes a barrier, which, though far less stubborn than the volcanic rocks of Cornwall, is yet more enduring than the clay: hence the land rushes proudly out on the domain of ocean. ”

“ Successive portions of this line of heights are known as the Western Downs, the White Horse Hills, the Chiltern Hills, the East Anglian Ridge, the Lincolnshire Wolds and the Yorkshire Wolds. The rivers from the gentle southern slopes of the Oolitic heights pass by deep valleys through the Chalk escarpments, and flow on to the Tertiary plains within. The typical scenery of the Chalk country is unrelieved by small streams of running water; the hills rise into rounded downs, often capped with fine clumps of beech, and usually covered with thin turf, affording pasture for sheep. ”

“ On the farther side, that to the rising sun, the chalk with dusky sandstone underneath rears itself into a bold headland, Haven Ball, that stands precipitously against the sea, as a white, cold shoulder exposed to it. Up a hollow of this hill, a combe as it is called, a mean track ascends to the downs which overhang the sea, and extend, partly in open tracts, in part enclosed, as far as Lyme Regis.
There is no highway. ”

“ Chalk, as a source of lime, has always been of high importance to builders, and, until improved transport brought alien materials into its old preserves, chalk was in general use for walling in the form of roughly squared blocks. ”

“ We have in England a kind of rock which constitutes at once an exceedingly clean recipient and a natural filter, and from which we can obtain water extremely free from mechanical impurities. I refer to the chalk formation, in which large quantities of water are held in store. Our chalk hills are in most cases covered with thin layers of soil, and with very scanty vegetation. Neither opposes much obstacle to the entry of the rain into the chalk, where any organic impurity which the water may carry in is soon oxidised and rendered harmless. ”

“ No better illustration can be found than the white earthy limestone, familiar to every one under the name of chalk. An undulating stratum of Chalk Rock, attaining not unfrequently a thickness of one thousand feet, may be said, speaking roughly, to underlie the southeastern half of England. ”

“ No deposits of domestic chalk have been exploited commercially. A somewhat inferior whiting, but one capable of being substituted for chalk in most cases, is manufactured from the waste fine material of limestone and marble quarries. ”

“ Chalk is not rich and fertile, like manure, it is altogether poor, barren stuff: you know that, or ought to know it. Recollect the chalk cuttings and banks on the railway between Basingstoke and Winchester—how utterly barren they are. Though they have been open these thirty years, not a blade of grass, hardly a bit of moss, has grown on them, or will grow, perhaps, for centuries. ”

“ If we follow the lines of fault, we may see, says M. Puggaard, along the planes of contact of the shifted beds, the marks of polishing and rubbing which the Chalk flints have undergone, as have many stones in the gravel of the drift, and some of these have also been forced into the soft Chalk. The manner in which the top of some of the arches of bent Chalk have been cut off in this and several adjoining sections, attests the great denudation which accompanied the disturbances, portions of the bent strata having been removed, probably while they were emerging from beneath the sea. ”

“ But on our southern coasts, the wall-sided cliffs, many hundred feet high, with vast needles and pinnacles standing out in the sea, sharp and solitary enough to serve as perches for the wary cormorant, confer a wonderful beauty and grandeur upon the chalk headlands. And in the East, chalk has its share in the formation of some of the most venerable of mountain ranges, such as the Lebanon. ”

“ Geographical Extent.—In a general sense, the cretaceous system ranges parallel to the oolitic formations from Yorkshire to Dorsetshire, and sends branches from the plains of Hampshire which border on the north and the south the Wealden formation of Kent and Sussex. The green sand formation is, in all parts of England, so closely connected with the chalk (except in Yorkshire, where it is almost deficient, and in Blackdown, Devon) , that it appears unnecessary to notice more than the characteristic range of the chalk. ”

“ Below the Chalk-rock we come to the Middle Chalk, or Chalk without flints, which may be so much as 350 feet in thickness, and rises in a rather steep slope or “step” from the underlying beds to be next mentioned. Flints are few and far between in the Middle Chalk, which forms the western slope of the Downs at Royston, as well as beyond the limits of the county at Luton, and so on to the Chiltern Hills. Fossils are much more numerous in the Middle than in the Upper Chalk. ”