In, or in close connection with the latter, the iron nodules are not to be found, but near the surface, where the quartz has softened and looks almost like a sandstone, the nodules occur in abundance.
Flint abounds there in amorphous nodules or blocks, and the nuclei, or cores, from which a succession of flakes have been struck, are of frequent occurrence among the relics of the Danish Stone age.
In Texas, the cretaceous limestones contain in places hornstone nodules distributed through them, like the flint nodules in the upper chalk beds of Europe.
The ancient flint pits have been explored; and the flint cores and rough-hewn nodules recovered.
As the ancient flint-miners sunk their pits in search of the levels where the flint abounds they would meet with frequent nodules of pyrites.
The flint is still abundant as ever, in nodules of a size amply sufficient for furnishing the largest palæoliths, in the localities both of France and England where such specimens of primitive art have been recovered by thousands.
There is a very hard ferruginous band, of which nodulesmay be found along the shore, full of beautifully perfect impressions of fossils, though the fossils themselves are gone.
Above this lies what is called the Lower Lobster bed, a brown clay and sand, in which are numerous nodulescontaining the small lobster Meyeria vectensis,--known as Atherfield lobsters.
Red ferruginous nodules with Ammonites lie on the shore, in the Chines, and on the Undercliff, some of the ammonites more or less converted into crystalline spar.
This consists of alternations of chalk with bands of Marl, and contains glauconite and also phosphatic nodules in the lower part.
The nodules frequently contain large Ammonites and other fossils.
Where the Upper Greensand is best developed, above the Undercliff, the passage beds are followed by 30 feet of yellow micaceous sands, with layers of nodules of a bluish-grey siliceous limestone known as Rag.
In the middle of the group are bands of nodules containing Macroscaphites gigas.
It also occurs as rounded nodules (mostly derived from the Lower Chalk) with a brown outer coat, and often showing a beautiful radiated metallic structure, when broken.
The writer has isolated these and grown them in pure culture as follows: The nodules are removed, if possible at an early stage in their growth, and placed for a few minutes in a steam steriliser.
By a simple process of hardening and using the microtome, excellent sections of the nodules can be obtained which show these bacteria in situ.
If thenodules from the rootlets of Leguminosæ be examined, the nitrogen-fixing bacteria can be readily seen.
As far back as 1794 Baillie drew attention to the grey miliary nodules occurring in tuberculous tissue which gave rise to the term "tubercles.
The Nitrogen-fixing Bacteria, found mainly in the nodules on the rootlets of certain plants.
In both these localities a characteristic condition is set up by small grey nodules appearing, which increase in size, giving an appearance of "grapes.
Baillie drew attention to grey miliary nodules occurring in tuberculosis, and called them "tubercles.
It may also occur as nodules in and under the skin, when it is known as "farcy.
The clay ironstone so extensively worked as an ore of iron occurs as nodules and beds in the Coal Measures of England and the United States, and the oolitic iron ore of the Cleveland district in Yorkshire forms beds in the Lias.
The nasal bones are in the form of nodules or flattened plates, applied closely to the frontals, and not forming any part of the roof to the nasal passage, which is directed upwards and backwards.
Phosphatic nodules for manure have been worked from the chloritic marl and Cambridge Greensand, and to some extent from the Middle Chalk.
They do not readily form nodules on the roots of the plants, seeming almost to know that there is no necessity for it.
After much experimenting, he made the important discovery that lupins which had nodules would grow in soil devoid of nitrogen, and that lupins which had no nodules would not grow in the same soil.
Nodules had formed on the roots of the beans in the third or inoculated jar only, thereby proving beyond the hope of the experimenter that soil inoculation was a possibility, at least in the laboratory.
Koch was making his greatest contributions to the world's knowledge of the germ theory of disease--that these nodules were the result of minute bacteria found in the soil.
It was plain, therefore, that the nodulesmust play an important, though mysterious, part in enabling the plant to utilise the free nitrogen of the air.
If these nodules were produced by bacteria, he argued that the bacteria must be present in the soil; and if they were not present, would it not be possible to supply them by artificial means?
So far as known they form nodules only on the roots of a few species of plants.
I found the sandstone formation of Cape Iroquois to reappear at the western termination of these heights on the open shores of the lake, where I noticed imbedded nodules of granular gypsum.
The limestone is, however, of a darker color, and contains numerous imbedded nodules of hornstone, and it emits a fetid odor on breaking.
About ten miles north of this point, the upper calcareous, or surface rock, embraces nodules of hornstone.
Small nodulesare formed and larger areas by their coalescence.
When the disease has reached an advanced stage, bacilli in small numbers continually pass into the blood and are distributed by this over the body, producing small nodules in many places.
The appearance of the above nodules of chalk surprised me, much at first, as they closely resembled water-worn pebbles, whereas the freshly-broken fragments had been angular.
Beneath the line of chalk nodules there was in parts hardly any fine earth free of flints, while in other parts there was a layer, 2.
A develop oval to kidney-shaped nodules attached to a stem extending from the cell substance.
As the incubation is prolonged these nodules increase in size, often measuring 1 mu to 2 mu in length; this nodule formation occurs at the expense of the cell protoplasm, and appears to be a marked characteristic of growth in whey.
Cultures of type B do not form nodules or clubs, but small spherical bodies more or less securely attached to the cell wall are seen.
He goes to one of the firms that makes a business of supplying nitrogen-fixing bacteria from the scabs or nodules of the clover roots and scatters these colonies over the field.
The bacteria that form the nodules on the roots of peas and beans have the power that man has not of utilizing free nitrogen.
Small nodules of iron-pyrites, about the size of a walnut, were blown out of the hole with incredible velocity.
As we drilled through this the gas blew out the nodules of iron-pyrites embedded in oil.
In this way we succeeded in penetrating through eighteen inches of a conglomerate mass of these iron-pyrites nodules embedded in heavy petroleum.
These nodules may increase in size, forming rather large, slightly raised plaques of yellowish-white color.
Most commonly there are nodules and plaques in the aorta and large branches together with thinning and sacculation of other portions of the vessels' walls.
There were no changes in the ascending aorta but in the descending portion there were scattered nodules and small calcified plaques.
The very hard sandstone still appeared, weathered to a purple colour; the lower part was most ferruginous, and not so hard as above; in the creek below I observed a red crust of clay and nodules of ironstone.
We crossed a low ridge of rich earth, in which were embedded nodules of limestone, and fragments of trap-rock.
The stream glided along at the rate of two miles per hour over a rock of ferruginous sandstone containing nodules of ironstone.
A yellow, highly calcareous sandstone occurred in the bed and banks of this stream, forming a stratum from two or three feet in thickness, and in parts of the upper surface nodules of ironstone were embedded.
The rock here is either a stratum of ironstone in irregular masses and nodules cemented together by a ferruginous base, or a very coarse sandstone, almost a quartzose conglomerate, forming cliffs, occasionally thirty feet or more in height.
The stellate nodules especially above, emit filamental rays in all directions, but are, notwithstanding, united by single, unpaired threads only.
The small-meshed net with well-defined, dark-colored nodules is distinctive, aside from the fact of the much smaller sporangia.
Under direct illumination many gatherings, especially where the sporangia are well blown out, show nodules of a bright orange tint.
Transverse section of sporangium; shows trabecular calcareous nodules of the capillitium, x 15.
The nodules are like those of tenella, but are much fewer.
In the cliffs of the southern coast of the Isle of Wight it contains bands of calcareous limestone withnodules of chert.
It was then observed that, in places where the secondary formations are unaltered, the uppermost consist of common Apennine limestone with nodules of flint, below which are shales, and at the base of all, argillaceous and siliceous sandstones.
As the older White Crag, presently to be mentioned, contains similar phosphatic nodules near its base, those of the Red Crag may be partly derived from this source.
Bands and nodules of clay-ironstone are common in coal-measures, and are formed, says Sir H.
The so-called coprolite bed, found near Farnham, in Surrey, and near Cambridge, containsnodules of phosphate of lime in such abundance as to be largely worked for the manufacture of artificial manure.
Such nodules of limestone have often a shell or other foreign body in the centre.
The phosphatic nodules often collect fossil crabs and fishes from the London Clay, together with the teeth of gigantic sharks.
In some of the amygdaloidal traps of Scotland, where the nodules have decomposed, the empty cells are seen to have a glazed or vitreous coating, and in this respect exactly resemble scoriaceous lavas, or the slags of furnaces.
Small nodules of azurite used by the Indians in decorating their altars, &c.
The raphe confined within a sigmoid keel or extension of the valve; the central and terminalnodules indistinct.
Amphora in which the valves appear in zone view with the median nodules of both valves on the same side.
Valve lunate; a raphe sometimes partially formed with terminal nodules near the edges.
In a valve from Port Penn, Delaware Bay, two nodules occur nearly opposite each other.
In this species the raphe and nodules can be seen only when the valve is examined at right angles to its usual position.
Examples of this are chert nodules in limestone; flint nodules in chalk; clay-ironstone balls in shale, &c.
In many cases, certain mineral matter which was originally diffused through a rock has segregated so as to form nodules and irregular layers.
According to my own observation on the scarlet runner bean these nodules are more plentiful upon the roots which grow superficially than upon those which run deeply.
Thus, a siliceous limestone becomes, by the segregation of the silica, a pure limestone containing nodules of chert, which are usually arranged in lines parallel with the stratification.
Most nodules of flint and chert, quartz, geodes, concretions of pyrite, and many hollow iron-balls are good illustrations of this class.
It is usually associated with folded strata, and often with distorted nodulesor fossils.
A similar history accounts for the curious nodules called "false coral" so common in moderately deep water in Long Island Sound.
This is what has happened: The vertebrae have grown together, and the backbone is a tube upon which the original nodulesin the skin have become fixed, and have broadened into the central line of plates.
They are formed of very compact nodules of brown hematite, which have been ground into form and polished with great labor.
With these relics, were found several large nodules of similar material, from which portions had been chipped off, exposing a nucleus, around which the accretion seems to have taken place.
These nodules are covered to the depth of half an inch, with a calcario-silicious deposit, white, and of great hardness.
Such nodulesare found in the secondary limestone formations.
Fremont observed some small nodules in the rocks of the «Sierra Nevada», lying to the eastward of the valley of the Sacramento.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "nodules" in a variety of sentences. We hope that you will now be able to make sentences using this word.
