Well-worn pebbles of amorphous quartz (agate, chalcedony, jasper, &c.) are found in the stratified drift along the western side of the Tertiary region of the state, and from Columbus northward.
Ignoring temperature effect, and taking the density as a function of the pressure, surfaces of equal pressure are also of equal density, and the fluid is stratified by surfaces orthogonal to the lines of force; n ap, dy, P d z, or X, Y, Z (4) are the partial differential coefficients of some function P, =fdplp, of x, y, z; so that X, Y, Z must be the partial differential coefficients of a potential -V, such that the force in any direction is the downward gradient of V; and then dP dV (5) ax + Tr=0, or P+V =constant, in which P may be called the hydrostatic head and V the head of potential.
The rocks here concerned are the extension of the same stratified Palaeozoic formations already described as occurring~in the Appalachian region and around the Great Lakes.
The Hexapoda, being aerial, terrestrial and fresh-water animals, are but occasionally preserved in stratified rocks, and our knowledge of extinct members of the class is therefore fragmentary, while the description, as insects, of various obscure fossils, which are perhaps not even Arthropods, has not tended to the advancement of this branch of zoology.
The greater part of Tunisia is composed of sandstones, marls and loosely stratified deposits belonging to the Pliocene and Quaternary periods.
Are composed chiefly of comminuted shells drifted and deposited by the wind, and they are very irregularly stratified, as is usually the case with wind-blown deposits.
In a north-eastern section, practically all of New England is occupied by the older crystalline belt; the corresponding northern part of the stratified belt in the St Lawrence and Champlain-Hudson valleys on the inland side of New England is comparatively free from the ridge-making rocks which abound farther south; and here the plateau member is wanting, being replaced, as it were, by the Adirondacks, an outlier of the Laurentian highlands of Canada which immediately succeeds the deformed stratified belt west of Lake Champlain.
In a south-western section the crystalline belt again assumes importance in breadth and height, and the plateau member maintains the strength that it had in the middle section, but the intermediate stratified belt again has fewer ridges, -because of the infrequence here of ridge-making strata as compared to their frequency in the middle section.
Ment of its drainage: its chief rivers rise in the plateau belt and flow across the ridges and valleys of the stratified belt and through the uplands of the crystalline belt to the sea.
The rivers which most perfectly exemplify this habit are the Delaware, Susquehanna and Potomac; the Hudson, the north-eastern boundary of the middle section, is peculiar in having headwaters in the Adirondacks as well as in the Catskills (northern part of the plateau); the James, forming the south-western boundary of the section, rises in the inner valleys of the stratified belt, instead of in the plateau.
For the most part the rivers follow open valleys along belts of weak strata; but they frequently pass through sharp-cut notches in the na1row ridges of the stratified beltthe Delaware water-gap is one of the deepest of these notches; and in the harder rocks of the crystalline belt they have eroded steep-walled gorges, of which the finest is that of the Hudson, because of the greater height and breadth of the crystalline highlands there than at points where the other rivers cross it.
In the north-west, before descent is made to the lowlands of the stratified belt (St Lawrence-Champlain-Hudson valleys, described later on as part of the Great Appalachian valley), and at the same time the rising uplands are diversified with monadnocks of increasing number and height and by mature valleys cut to greater and greater depths; thus the interior of New England is moderately mountainous.
The Appalachian trends (N.E.S.W.) that are so prominent in the stratified belt of the middle Appalachians, and are fairly well marked in the crystalline belt of New Jersey and Pennsylvania, are prevailingly absent in New England.
In consequence of the general south-eastward slope of the highlands and uplands of New England, the divide between the Atlantic rivers and those which flow northward an~j westward D ~t into the lowland of the stratified belt in Canada and r New York is generally close to the boundary of these two physiographic districts.
In New England also a wellestablished drainage undoubtedly prevailed in preglacial times; but partly in consequence of the irregular scouring of the rock floor, and even more because of the very irregular deposition of unstratified and stratified drift in the valleys, the drainage is now in great disorder.
It is a peculiar feature of the drainage in North Carolina that the headwaters lie to the east of the highest mountains, and that the chief rivers flow north-westward through the mountains to the broad valley lowland of the stratified belt and then through the plateau, as the members of the Mississippi system.
As in all such cases, the plain consists of marine (with some estuarine and flu viatile) stratified deposits, more or less indurated, which were laid down when the land stood lower and the sea had its shore line farther inland than to-day.
A curious feature appears in northern Pennsylvania: here the lateral pressure of the Palaeozoic mountain-making forces extended its effects through a belt about fifty miles wider than the folded belt of the Hudson Valley, thus compressing into great rock waves a part of the heavy stratified series which in New York lies horizontal and forms the Catskills; hence one sees, in passing south-west from the horizontal to the folded strata, a beautiful illustration of the manner in which land sculpture is controlled by land structure.
The valleys by which the uplands are here and there trenched to moderate depth appear to be, in part at least, the work of streams that have been superposed upon the perieplain through the now removed cover of stratified rocks.
When the oldland and its overlap of stratified deposits were elevated again, the overlapping strata must have had the appearance of a coastal plain; but that was long ago; the strata have since then been much eroded, and to-day possess neither the area nor the smooth form of their initial extent.
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.
The Pocky The upturned stratified formations wrap around the Mountains.
Along the eastern side of the Front Range in Colorado most of the upturned stratified formations have been so well worn down that, except for a few low piedmont ridges, their even surface may now be included with that of the plains, and the crystalline core of the range is exposed almost to the mountain base.
The majority of the lichens, however, possess a stratified thallus in which the gonidia are found as a definite layer or layers embedded in a pseudoparenchymatous mass of fungal hyphae, i.e.
But it is divided longitudinally by a well-marked belt of stratified deposits, known as the zone of the Briangonnais, composed chiefly of Carboniferous, Triassic and Jurassic beds.
CARBONIFEROUS SYSTEM, in geology, the whole of the great series of stratified rocks and associated volcanic rocks which occur above the Devonian or Old Red Sandstone and below the Permian or Triassic systems, belonging to the Carboniferous period.
The stratified rocks of this system include marine limestones, shales and sandstones; estuarine, lagoonal and fresh-water shales, sandstones and marls with beds of coal, oil-bearing rocks, gypsum and salt.
No assemblage of stratified rocks has received such careful and detailed examination as the Carboniferous system; consequently our knowledge of the stratigraphical sequence in isolated local areas, where the coals have been exploited, is very full.
Woodward, The Geology of England and Wales, and ed., 1887.) The conception of an underlying " solid " geological structure covered by a superficial mantle of " drift " is still retained for certain practical purposes; thus, the Geological Survey of Great Britain issues many of the maps in two forms, the " Solid Edition," showing the " solid geology," which embraces all igneous rocks and the stratified rocks older than Pleistocene, and the " Drift Edition," which shows only such older strata as are unobscured by drift.
It is unstratified; but by the action of water on it, stratified deposits have been formed, some of clay, containing remains of arctic animals, some, and very extensive ones, of sand and gravel.
It has a stratified cone showing a long period of activity.
The lower Nile valley, however, forms an exception; flint implements of a palaeolithic type have been found near Thebes, not only on the surface of the ground, which for several thousand years has been desert owing to the contraction of the river-bed, but also in stratified gravel of an older date.
The oldest rocks in this large area are a stratified series of mica-schists, limestones and quartzites, with numerous intrusive sheets of diorite, the whole having been metamorphosed by pressure, with frequent overfolding.
There are large deposits of stratified clay along the shores of Lake Michigan, from which is made a cream-coloured brick, so largely used in Milwaukee that that city has been called the "cream city"; the total value of clay products in 1907 was $1,127,819 and in 1908 $95 8, 395.
In geology, a fold is a bend or curvature in the stratified rocks of the earth's crust, whereby they have been made to take up less horizontal space.
The object is really viewed through a horizontally stratified medium consisting of a central sheet of maximum refractive index, overand under-laid by sheets of decreasing refractive power.
The stratified rocks in the highlands strike north and south, as if they had been crumpled into folds, in Upper Palaeozoic times, by pressure from east to west.
Above the plain, also in Bingham county) is an upraised block of stratified basalt.
The stratified rocks of the Great Plains, the Parks, and the Plateaus contain enormous quantities of coal.
Until the fourth decade of the 19th century all stratified rocks older than the Carboniferous had been grouped by geologists into a huge and indefinite "Transition Series."
The Vindhyans are well-stratified beds of sandstone and shale, with some limestones.
In general the stratified deposits lie nearly flat and in regular conformable succession, the lowest resting upon the floor of ancient crystalline rocks.