They yield valuable coals, clays, marls and ganister.
Clays and mineral waters are, however, widely distributed.
Its upheaval above the great sea which submerged all the north-west of the Indian peninsula long after the Himalaya had massed itself as a formidable mountain chain, belongs to a comparatively recent geologic period, and the same thrust upwards of vast masses of cretaceous limestone has disturbed the overlying recent beds of shale and clays with very similar results to those which have left so marked an impress on the Baluch frontier.
The Keuper clays yield material for bricks.
Kaolin, fire-clays and brick-clays are common to all the states.
The best soils are in the west section, where limestone clays or shell marls are common.
The oak grows most luxuriantly on deep strong clays, calcareous marl or stiff loam, but will flourish in nearly any deep well-drained soil, excepting peat or loose sand; in marshy or moist places the tree may grow well for a time, but the timber is rarely sound; on hard rocky ground and exposed hillsides.
The Cambrian is represented by blue clays, ungulite sandstones and bituminous slates in Esthonia and St Petersburg.
For days together the traveller sees no other vegetation; even this, however, disappears as he approaches the regions recently left dry by the Caspian, where saline clays, bearing a few Salsolaceae, or mere sand, take the place of the black earth.
Overlying the Tuscaloosa are the Eutaw sands, characterized by sandy laminated clays, and yellow, orange, red and blue sands, containing lignite and fossil resin.
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.
It is marked by grey clays and sands, lignitic fossiliferous clays, beds of lignite or brown coal, sometimes 8 ft.
The Jackson formation south-west of the Lisbon beds, is made up chiefly of grey calcareous clay marls, bluish lignitic clays, green-sand and grey siliceous sands.
The Grand Gulf group, of formations of different ages, consisting of sands, sandstones and clays, and showing a few fossil plants, but no marine fossils, extends southward from the last to within a few miles of the coast, and is 750-800 ft.
Its materials are pebbles, clays and sands of various' colours from white to deep red, tinged with peroxide of iron, which sometimes cements the pebbles and sands into compact rocks.
They yield valuable coals, clays, marls and ganister.
In regions where climatic conditions are favourable, cotton grows more or less successfully on almost all kinds of soil; it can be grown on light sandy soils, loams, heavy clays and sandy " bottom " lands with varying success.
Sandy soils are made thereby too dry and leachy, and it is a questionable proceeding to turn the heavy clays upon the top. Planters are, as a result, divided in opinion as to the wisdom of subsoiling.
The earlier wells in Pennsylvania consisted of three sections, the first formed of surface clays and gravels, the second of stratified rocks containing water, and the third of stratified rocks, including the oil-sands, usually free from water.
Eastwards the mountain system, the Jebel Sangeli, maintains the same general character as far as Bandar Gori (Las Korai), where the precipitous northern cliffs approach within 200 or 300 yards of the gulf, their bare brown rocks and clays presenting the same uninviting appearance as the light brown hills skirting the Red Sea.
Clays of all qualities and colours abound.
Tobacco is most generally cultivated on loose red soils, which are rich in clays and silicates; and sugar-cane preferably on the black and mulatto soils; but in general, contrary to prevalent suppositions, colour is no test of quality and not a very valuable guide in the setting of crops.
They consist chiefly of sands and clays of aeolian and freshwater origin.
It is found in the form of oxide (silica), either anhydrous or hydrated as quartz, flint, sand, chalcedony, tridymite, opal, &c., but occurs chiefly in the form of silicates of aluminium, magnesium, iron, and the alkali and alkaline earth metals, forming the chief constituent of various clays, soils and rocks.
Even in the soils which farmers speak of as stiff clays it is rarely present to the extent of more than I or 2%.
Where the soil grains are quite free from each other the smaller grains tend to fill up the spaces between the larger ones; hence it might be concluded that in clays the amount of pore-space would be less than in coarser sands.
This is the case in " puddled " clays, but in ordinary clay soils the excessively minute particles of which they largely consist tend to form groups of comparatively large composite grains and it is in such natural soils that the pore-space is largest.
In certain sandy soils and in a few stiff clays it may amount to less than 4%, while in others in limestone and chalk districts there may be 50 to 80% present.
The addition of small quantities of lime, especially in a caustic form, to stiff greasy clays makes them much more porous and pliable.
It is this power of creating a more crumbly tilth on stiff clays that makes lime so valuable to the farmer.
Generally speaking light poor lands deficient in organic matter will need the less caustic form or chalk, while quicklime will be most satisfactory on the stiff clays and richer soils.
Brick, potter's and tile clays are obtained most largely along the west border of the Coastal Plain, and fire-clay from the coal region of West Maryland; in 1907 the value of clay products was $1,886,362.
The clays used are exclusively American, much being obtained in Missouri.
Recently elevated marine clays, of post-glacial date, fringe the south-eastern coast, while gravels with marine shells, side by side with flint implements chipped by early man, have been lifted some 20 ft.
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.
The sands and clays found here are fine and soft, and as there is scant vegetation to protect the hillsides they are easily eroded by the rains.
Good clays for the manufacture of tile and brick are found at numerous places.
The valley, which extends from the borders of Sussex to Hythe, is occupied chiefly by the Weald clays, which contain a considerable number of marine and freshwater fossils.
Ironstone is found in the Wadhurst Clay, a subdivision of the Hastings beds, clays and calcareous ironstone in the Ashdown sand, but the industry has long been discontinued.
There are large deposits of glacial and residual clays and clay shales throughout the state.
They consist of fine clays with nodular calcareous concretions rich in fossils.
There are also deposits of clay suitable for making bricks, terra-cotta and tiles in nearly every county outside of this valley, and there are some pottery clays in Albany and Onondaga counties.