Chert sentence example

chert
  • Beds and nodules of chert are abundant in the upper parts of the limestone; at Bakewell it is quarried for use in the Potteries.
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  • 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.
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  • The Dolomite Series, known to the Dutch as " Olifants Klip," consists of a bluish-grey magnesian limestone with bands of chert.
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  • the Millstone Grit contains fragments of chert which can only have come from the waste of the earlier limestones.
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  • 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.
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  • 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.
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  • Chert is a coarser and less perfectly homogeneous substance of the same nature and composition as flint.
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  • metamorphosed basalt, chert and greywacke depending on quarry source.
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  • radiolarian chert is virtually absent.
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  • The piece was triangular, of pale gray chert, with fine pressure flaking, and evidence for retouch on the straight edge.
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  • \Voodford chert fioo ft.
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  • 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.
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  • In the limestone was found the flint or chert used for weapons and instruments in early times.
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  • Oman series; limestones and slates with beds of chert.
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  • The Upper Cretaceous is represented by limestones with bands of chert, and contains Ammonites, Baculites, Hippurites and other fossils.
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  • In the Cambrian limestones, as in their more recent analogues, layers and nodules of chert and phosphatized material are not wanting.
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  • The figures for the more important minerals are as follows: Gold ore, manganese ore and uranium ore are produced in small quantities, and the list of minerals worked in the United Kingdom also includes chalk, lead, alum, phosphate of lime, chert and flint, gravel and sand, zinc ore, gypsum, arsenic, copper, barytes, wolfram and strontium sulphate.
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  • There are also beds of chert, which are largely composed of radiolaria.
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  • Thus in the microcrystalline chalcedony the lustre is waxy, the fracture fibrous to even, and the external form botryoidal or stalactitic flint and chert are compact and have a splintery fracture: jasper is a compact variety intermixed with much iron oxide and clay and has a dull and even fracture.
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  • In limestones of various kinds it occurs as nodules and bands of chert and flint, being in this case of organic origin.
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  • 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.
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  • The upper beds of the third limestone are often dark colored, and contain layers of black chert in nodules.
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  • The pieces of gray chert were found on the tourist path below slopes too steep for human habitation.
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  • Figure 5. The aging process of Casa Montero's cherts: X-Ray diffraction pattern of opal and opaline chert obtained from the same nodule.
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  • In fewer instances, layers of the limestone seem to be converted into white chert, called china stone.
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  • chert nodules abound.
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  • chert grits, some small cavities, quartz dust in the clay matrix.
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  • chert fragments, with a few very small to large cavities from former grits.
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  • chert cobbles belonging to the terrace deposits.
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  • chert pebbles becoming more angular with depth (Carr and Blackley 1969 ).
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  • chert flake was visible at the surface of the feature.
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  • However, in comparison to Group 4, radiolarian chert is virtually absent.
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  • It contains a very high quartz and chert content, so that it is extremely friable.
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  • GW3 Thick walled, numerous small to medium chert grits, some small cavities, quartz dust in the clay matrix.
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  • A perfect solution tube can be seen in the roof and large chert nodules abound.
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  • opaline chert obtained from the same nodule.
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  • 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.
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  • Atoka formation (Chickahoc chert lentil) - 3200,,
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  • obsidian, chert, chalcedony, agate and quartzite, but to prehistoric man (see FLINT IMPLEMENTS below) flint must have been of great value and served many of the uses to which steel is put at the present day.
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  • The oldest, bordering the Lower Carboniferous, is the Tuscaloosa formation of clays and sands arranged as follows: dark clays, thin lignite seams, lignitic clays, sands and chert, and light clays; this formation is 5-15 m.
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