The limestone is sometimes changed in character by the proximity of the granitic mass or its veins, and acquires a more compact texture, like that of hornstone or chert, with a splintery fracture, and effervescing freely with acids.
A new period of repose then ensued, during which various sulphurets were introduced, together with hornstone quartz, by which angular fragments of the older quartz before mentioned were cemented into a breccia.
The flint or hornstone which occurs in that region, is a beautiful material of a dark color, resembling somewhat the real flint found in nodules in the cretaceous formations of Europe.
The geological locality of hornstone is remarkable; for it occurs in both ancient and recent formations.
In Siberia, native gold occurs in a hornstone at Schlangenberg or Zmeof, and at Zmeino-garsk in the Altai mountains, accompanied with many other ores.
Hornstone is less brittle than flint; and by its infusibility before the blowpipe it may be distinguished from petrosilex, which it resembles in external appearance.
The hornstone which occurs in secondary limestone is called chert by the English miners.
It is calcined to make it crushable, under stamp-pestles driven by machinery, then ground fine in hornstone mills, as represented in figs.
A series of limestones usually charged with considerable quantities of siliceous matter in the shape of hornstone or chert (Lat.
Before leaving the Devonian vegetation, it may be mentioned that the hornstone or chert so abundant in the Corniferous limestone of North America has been shown to contain the remains of various microscopic plants (Diatoms and Desmids).
In regions where flint or hornstoneis not available, the quartzite appears to have been most commonly resorted to.
But the transportation of the unwrought blocks of hornstone to the work-yards in the valley would have involved great labour in the construction of roads, as well as of sledges or waggons suited to such traffic.
In Texas, the cretaceous limestones contain in places hornstone nodules distributed through them, like the flint nodules in the upper chalk beds of Europe.
Following up the stream I came to some rapids, where the stream is crossed by large beds of hornstone and porphyry rocks, excessively hard, and pitched up at right angles, or with a bold dip to the north.
These hills are of limestone, and rounded, resting upon others of hornstone and jasper.
This description of rock is on an average of five feet, covering a substratum of a species of cias limestone of a bluish colour, imbedding nodules of hornstone and organic remains.
In many parts of the excavation masses of a bluish white flint and hornstone were found enclosed in or incrusting the fetid limestone.
Hornstone is more brittle than flint and has a splintery rather than a conchoidal fracture.
It is simply a black variety of crypto-crystalline quartz, differing from jasper in being tougher and of finer grain and from hornstone in not being splintery.
The sandstone has been indurated, and has assumed a texture approaching to hornstonenear the junction.
The limestone is sometimes changed in character by the proximity of the granitic mass or its veins, and acquires a more compact texture, like that of hornstone or chert, with a splintery fracture, effervescing feebly with acids.
This variety of hornstone I have seen in every part of New England in the form of Indian arrowheads, hatchets, chisels, etc.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "hornstone" in a variety of sentences. We hope that you will now be able to make sentences using this word.
