Chert sentence example
Celts, of the usual late neolithic type, were generally of green jasper; hoe-blades (looking almost exactly like palaeolithic haches a main) of chert or coarse limestone; hammers of granite; mace-heads, of identical type with the early Egyptian, of diorite and limestone; nails of obsidian or smoky quartz, often beautifully made.
The Dolomite Series, known to the Dutch as " Olifants Klip," consists of a bluish-grey magnesian limestone with bands of chert.
The old land area still existed to the north, but doubtless much reduced in height; against this land, detrital deposits still continued to be formed, as in Scotland; while over central Ireland and central and northern England the clearer waters of the sea furnished a suitable home for countless corals, brachiopods and foraminifera and great beds of sea lilies; sponges flourished in many parts of the sea, and their remains contributed largely to the formation of the beds of chert.
The fossils from the Rhaetic beds belong to the Avicula contorta zone, those from the Lias to the Ammonites angulatus zone, while the blocks of limestone with chert contain Inoceramus, Cretaceous foraminifera and other organisms. The materials yielding these fossils are embedded in a course volcanic agglomerate which gives rise to crags and is pierced by acid and basic igneous ricks.
Chert is a coarser and less perfectly homogeneous substance of the same nature and composition as flint.Advertisement
The piece was triangular, of pale gray chert, with fine pressure flaking, and evidence for retouch on the straight edge.
The beds of chert are utilized in the pottery industry, and some of the harder and more crystalline limestones are beautiful marbles, capable of taking a high polish.
In the limestone was found the flint or chert used for weapons and instruments in early times.
The Upper Cretaceous is represented by limestones with bands of chert, and contains Ammonites, Baculites, Hippurites and other fossils.
In the Cambrian limestones, as in their more recent analogues, layers and nodules of chert and phosphatized material are not wanting.Advertisement
There are also beds of chert, which are largely composed of radiolaria.
In limestones of various kinds it occurs as nodules and bands of chert and flint, being in this case of organic origin.
In the latter place they contain workable coal-seams. The Carboniferous Limestone often contains black flint (chert), and at some horizons conglomerates occur, the pebbles being derived from the unconformable ridges of the " Caledonian " land.
The upper beds of the third limestone are often dark colored, and contain layers of black chert in nodules.
The pieces of gray chert were found on the tourist path below slopes too steep for human habitation.Advertisement
In fewer instances, layers of the limestone seem to be converted into white chert, called china stone.
However, in comparison to Group 4, radiolarian chert is virtually absent.
It contains a very high quartz and chert content, so that it is extremely friable.
A perfect solution tube can be seen in the roof and large chert nodules abound.
Flint and chert were employed for knives, etc., but with none of the marvellous skill and artistry of the predynastic Egyptian flint-knapper; the early Babylonian used comparatively simple flakes and the wonderful serration of the Egyptian knives was unknown to him though he made the saw-blades.Advertisement
Atoka formation (Chickahoc chert lentil) - 3200,,
Beds and nodules of chert are abundant in the upper parts of the limestone; at Bakewell it is quarried for use in the Potteries.