But this symmetry often gives place to a more or less tortuous course with lateral joints in various apparently random directions, more especially where in stratified rocks the beds have diverse lithological characters.
Desiccation, as shown by the cracks formed in mud when it dries, has probably been instrumental in causing jointing in a limited number of cases among stratified rocks.
In crystalline (igneous) rocks, bedding is absent and very often there is no horizontal jointing to take its place; the joint planes break up the mass more irregularly than in stratified rocks.
As they serve, in conjunction with bedding, to divide stratified rocks into large quadrangular blocks, their effect on cliffs and other exposed places is seen in the splintered and dislocated aspect so familiar in mountain scenery.
An important feature in the joints of stratifiedrocks is the direction in which they intersect each other.
A columnar jointing has often been superinduced upon stratified rocks by contact with intrusive igneous masses.
Two high cones stood above the immense red-baked wall at its eastern end, where it was in huge blocks stratified in thicknesses varying from 15 to 20 ft.
Even the stratified rocks, though they seemingly have not been melted, give evidence in some instances of having been subjected to the action of heat.
All doubt as to the mode of origin of stratified rocks being thus removed, the way was opened for a more favorable consideration of that other Huttonian doctrine of the extremely slow denudation of land surfaces.
The rugged and uneven surfaces of mountains, the tilted and broken character of stratified rocks everywhere, are the standing witnesses of these gigantic upheavals.
It is furnished by every bed of limestone, every outcropping fragment of fossil-bearing rock, every stratified cliff.
In these softer layers the differences which are due to the stratified precipitation still remain.
Students disputed whether the conjunctiva extended over the cornea or not, and worried themselves over Gaultier de Claubry's stratified layers of the skin, or Breschet's blennogenous and chromatogenous organs.
But the readers of Hugh Miller remember what a variety of fossils he found in the stratified rocks of his little island, and the museums are full of just such objects.
It is impossible to tell from geological data the actual age of the stratified rocks; but this is not required.
This would not, however, represent the age of the stratified rocks.
The stratifiedrocks may be as old as this, but assuredly they are not if gravitation was the only source from which the sun derived his energy.
There is nothing in the stratified rocks which affords any support to the idea of great tidal waves having swept over the land, at least since the time when life began on our globe.
It is therefore evident that the materials composing our stratifiedbeds must have passed through many cycles of destruction and re-formation.
Few geologists, I think, who will duly reflect on the subject, will deem it too much to say that the present existing stratified rocks have on an average passed at least thrice through the cycle of destruction and re-formation.
We have seen that it is impossible to determine the actual age of the earth from the stratified rocks, even if we knew with perfect accuracy their present total amount.
If we knew the total quantity ofstratified rock on the globe, we could easily tell the time that would be required for its formation.
The epithelium is here stratified instead of simple columnar, and the folds into which it is thrown are broader and less numerous than in the duodenum above described.
The mouth and pharynx are lined at this stage with a thin, stratified epithelium, which consists of a basal layer of rather tall columnar cells and one or two superficial layers of flattened cells.
Immense torrents of water had filled in the inlet with stratified moraine-material, and for centuries favorable climatic conditions allowed forests to grow upon it.
In the old stratified moraine banks, trunks and branches of trees showing but little sign of decay occur at a height of about a hundred feet above tide-water.
I sailed three or four miles down the east coast of the inlet with the Reid party's cook, who is supposed to be an experienced camper and prospector, and landed at a stratified moraine-bank.
The two wings advanced over the washed and stratified moraine deposits have little or no motion, melting and receding as fast, or perhaps faster, than it advances.
The stratifieddrift on the west side all the way from top to base contains fossil wood.
This great discovery of the order of succession of the British stratified rocks, established by their fossil contents, is due to William Smith, the father of English geology.
But the classification of the stratified rocks has been carried farther than this.
Omitting the small epochs of time, this table is as follows, in descending order:-- Table of the British Stratified Rocks.
And it is quite possible that even granite may in some cases be the result of the melting and consolidation under great pressure of certain familiar stratified rocks.
Pebble-beds, called by geologists conglomerates, are met with among the stratified rocks; and their story is easily read by studying what takes place at the present day on our seashores.
Undoubtedly the most characteristic scenery formed by stratified rocks is to be seen in those places where the "bedding" is horizontal, or nearly so, and the strata are massive.
By combining the two principles referred to above, geologists have arranged the great series of British stratified rocks into certain groups, each indicating a long period of time.
Now, geologists find that some limestone formations met with in the stratified rocks have certainly been formed in this way; for example, certain parts of the great "mountain limestone.
The appearance of the country was remarkable, from being covered by a thick crust of common salt, and of a stratified saliferous alluvium, which seems to have been deposited as the land slowly rose above the level of the sea.
The lofty mountains, their summits marked with a few patches of snow, stood well separated from each other; the valleys being filled up with an immense thickness of stratified alluvium.
No one fact in the geology of South America interested me more than these terraces of rudely-stratified shingle.
The village is situated at the bottom of a valley, bounded by lofty and jagged walls of stratified lava.
It varies in width from thirty to sixty yards, and its surface is level and smooth; it is composed of obscurely-stratified hard sandstone.
Instead of this, the Incas Bridge consists of a crust of stratified shingle cemented together by the deposits of the neighbouring hot springs.
The remains at Punta Alta were embedded in stratified gravel and reddish mud, just such as the sea might now wash up on a shallow bank.
The mineral springs of Cauquenes burst forth on a line of dislocation, crossing a mass of stratified rock, the whole of which betrays the action of heat.
Having entered the harbour, it appears fine and spacious, with cliff-formed shores of horizontally stratified sandstone.
The mountains around are nearly all built of horizontal stratified rocks.
The steam seeks an outlet through fissures made in the plutonic rocks by volcanic forces and through seams in the upper crumpled and pitchedstratified formations.
The work of deposition went on and sandstone was overlaid by stratified clay.
A laminated clay forms the lowest bed, above which comes a stratified sand, and this is followed by a clay containing boulders, each of these deposits being about twenty-five feet thick.
Though the Secondary rocks of the Alps have undergone, in places, some modification and mineral changes, these are very different from the metamorphism of those crystalline schists which have a stratified origin.
He also examined some sections of stratified drifts between Montreal and Quebec, but without obtaining any fossils, though they had been found by Captain Bayford and others.
They consist of well-stratified sands, with occasional gravelly beds, and contain a fair number of shells, both broken and whole, the fauna being slightly more arctic than that which still inhabits the neighbouring sea.
Naturally so, for he had been working his way from Buxton on the look-out for glacial deposits and studying especially the stratified drifts on the hills east of Macclesfield, 1,200 feet above the sea.
The sandstone is fine, of a deep red colour, indistinctly stratified and traversed in various directions by veins filled principally with sulphate of lime.
From the great development of these inner beds, a person walking round the rim of this crater might fancy himself on a circular anticlinal ridge of stratified sandstone and conglomerate.
On the northern side of the Green Mountain a thin seam, about an inch in thickness, of compact oxide of iron, extends over a considerable area; it lies conformably in the lower part of the stratified mass of ashes and fragments.
They all agree in the laminated and stratified character of the whole series; and Humboldt speaks of some of the beds of obsidian being ribboned like jasper.
Numerous springs oozed and trickled from the stratified conglomerate along the edges, sides, and bottoms of the ravines.
In this land of weather-worn porphyry and inter-stratified sandstone, natural caves are met with everywhere, in which the people find a convenient and safe shelter.
I shall place before you three kinds of evidence entirely based upon what is known of the forms of animal life which are contained in the series of stratified rocks.
That, I say, is the natural and obvious teaching of the circumstantial evidence contained in the stratified rocks.
They furnish us with a record, the general nature of which cannot be misinterpreted, of the kinds of things that have lived upon the surface of the earth during the time that is registered by this great thickness of stratified rocks.
The whole series of fossiliferous stratified rocks must be referred to the last two days; and neither the Carboniferous, nor any other, formation can afford evidence of the work of the third day.
We can pursue this evidence until we reach the lowest of the stratified rocks, in which we lose the indications of life altogether.
Where then can we find a stratified or bedded structure now being formed over the ocean bottom?
But we now know that there is no means of producing a stratified formation in this "deep and clear water," and hence that some revolution of nature is implied by the conditions in which we find them.
Its course for several miles from its head is over the stratified rock, and into this it has worn a channel that presents most striking and peculiar features.
It dislikes a limestone soil, but seems to prefer the detritus of the stratified rock.
The sedimentary or stratified rocks are formed of particles carried down by water and deposited at the bottom of the primeval seas from which they have been upheaved in the course of geological changes.
Such are the general characters of the three great classes of stratified rocks; any attempt to particularise the numerous varieties of each would lead us far beyond the limits of the present work.
Limestone is one of the most widely distributed of the stratified rocks, and in different localities occurs of very different composition.
The geological formations of the second period consist of stratified masses of sand and gravel, called the "ancient alluvium" by MM.
Both specimens were thrown out by the workmen on the same day from the lowest bed of stratified gravel and sand, 13 feet thick, containing bones of the elephant, deer, and ox, and many freshwater shells.
To the north of Cromer are other fine illustrations of contorted drift reposing on a floor of Chalk horizontally stratified and having a level surface.
Prestwich, Evans, and Wyatt, and we collected ten species of shells from the stratified drift Number 3, or the beds overlying the lowest gravel from which the flint implements had been exhumed.
They were embedded in stratified clays, with the unstratified boulder till both above and below them, and in the overlying unstratified drift were some boulders of granite which must have come from distances of 60 miles at the least.
Germination was higher for nuts planted in the fall than for nuts stratified on the same day for spring planting, although the difference was significant only in the second test.
Stratified at 45-50° F subsequently soaked in water prior to planting Nuts from the three seedlots were kept separate and planted in random plots in three seedbeds.
Germination and Stratification It is known that either fall- or spring-planted walnuts germinate readily if the nuts are viable and if those planted in the spring are properly stratified over winter.
But in the opinion of all our first naturalists and geologists, the period occupied in the formation of the known stratified rocks only represents a portion, and perhaps a small portion, of geological time.
The materials of all the stratified rocks of the globe have been obtained from the dry land.
From the preceding considerations we shall be better able to appreciate the calculations as to the thickness of stratified deposits made by geologists.
Continental islands are always more varied in their geological formation, containing both ancient and recent stratified rocks.
Owing to this thinning out of stratified rocks, they are on the whole of far less extent than is usually supposed.
