The soil is a clayey or a sandy loam, and very fertile except in the Usar tracts, where there is a saline efflorescence.
The buildings, which are mostly of red brick, are conspicuous against the gray clayey and sandy soil.
The soil is exceedingly rich and well adapted to all kinds of agricultural purposes, and for the most part is composed of a rich black loam reposing on a grey sandy clay, though occasionally it exhibits a light yellow clayey texture.
The hornbeam thrives well on stiff, clayey, moist soils, into which its roots penetrate deeply; on chalk or gravel it does not flourish.
In central Europe it thrives best in enclosed, preserved waters, with a clayey or muddy bottom and with an abundant vegetation; it avoids clear waters with stony ground, and is altogether absent from rapid streams. The tench is distinguished by its very small scales, which are deeply imbedded in a thick skin, whose surface is as slippery as that of an eel.
It is deeper and more sandy where granite is the underlying rock, deeper and more fertile on the north-western than on the south-eastern mountain slopes, and shallower and more clayey where slate is the underlying rock.
Much of the soil of the desert appears to be alluvial; there are numerous traces of streams having formerly passed over it, and still, where irrigation is at all practicable, fertility in the clayey tract follows; but the rains are scanty, the wells few and generally 100 ft.
For dry situations almond stocks are preferable, but they are not long-lived, while for damp or clayey foams it is better to use certain kinds of plums. Double-working is sometimes beneficial; thus an almond budded on a plum stock may be rebudded with a tender peach, greatly to the advantage of the latter.
The ground was originally a Roman Cemetery, and about the year 1576 bricks were largely made from the clayey earth, the recollection of which is kept alive in the name of Brick Lane.
The original meaning of Urra was perhaps " clayey soil," but it came to signify " the upper country " or " highlands," kengi being " the lowlands."
The river bottoms the soil is for the most part a black clayey loam lacking in natural drainage, but on the " bench lands " higher up there is a deep layer of sandy loam beneath which is a bed of gravel.
The Thanet beds resting on chalk form a narrow outcrop rising into cliffs at Pegwell Bay and Reculver, and consist (1) of a constant base bed of clayey greenish sand, seldom more than 5 ft.
The till is presumably made in part of preglacial soils, but it is more largely composed of rock waste mechanically comminuted by the crccpiiig ice sheets; although the crystalline rocks from Canada and some of the more resistant stratified rocks south of the Great Lakes occur as boulders and stones, a great part of the till has been crushed and ground to a clayey texture.
In case of adhesive clayey subsoil this can generally be secured by placing over the sloping bottom a good layer of coarse rubbly material, communicating with a drain in front to carry off the water, while earthenware drain tubes may be laid beneath the rubble from 8 to To ft.
The clayey siderite of the British coal measures is called " clay band," and that containing bituminous matter is called " black band."
About two-thirds of the ore mined is clayey siderite.
The salt has been dissolved out of its original matrix, and the cavity so formed has then been filled with fine clayey or other mineral matter, forming a cubic cast.
These are still largely used, and are prepared by burning limestones containing clayey matter.
Their poor soils are distinctively sandy, those of the lowlands clayey; but these elements are usually found combined in rich loams characterized by the predominance of one or the other constituent.
The soil is for the most part clayey, resting on a bed of chalk, and is, in general, fertile and well tilled.
In the upper part of the district the soil is sandy, while in the lower part it is clayey and produces finer crops.
Attention has been called to the fact that the bare rocks and steep gradients which are common in the Western Division allow of the heavy rainfall running off the surface rapidly, while the flat and often clayey lands of the Eastern Division retain the scantier rainfall in the soil for a longer time, so that for agricultural purposes the effect of the rainfall is not very dissimilar throughout the country.
The greater part of the Maremma now affords pasture to large herds of horses and half-wild cattle, but on the drier parts corn is grown, the people coming down from the hills to sow and to reap. The hill country just inland, especially near Volterra, has poor soil, largely clayey, and subject to landslips, but is rich in minerals.
The common souslik lives in dry, treeless plains, especially on sandy or clayey soil, and is never found either in forests or on swampy ground.
To the south-west the clayey soil becomes saline.
The low clayey or sandy shores are subject to erosion by waves.
But like every pure theory the principles of conjugate pressures in earth may lead to danger if not applied with due consideration for the angle of repose of the material, the modifications brought about by the limited width of artificial embankments, the possible contraction away from the masonry, of clayey materials during dry weather for some feet in depth and the tendency of surface waters to produce scour between the wall and the embankment.
The Mississippi embayment is in parts predominantly sandy, in others clayey; it is mainly under timber.