Chalk Bluff Township, Clay County, Arkansas
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel. Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity. It is also used for " blackboard chalk" for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum. Description Chalk is a fine-textured, earthy type of limestone distinguished by its light color, softness, and high porosity. It is composed mostly of tiny fragments of the calcite shells or skeletons ...
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The Needles
The Needles is a row of three stacks of chalk that rise about out of the sea off the western extremity of the Isle of Wight in the English Channel, United Kingdom, close to Alum Bay and Scratchell's Bay, and part of Totland, the westernmost civil parish of the Isle of Wight. The Needles Lighthouse stands at the outer, western end of the formation. Built in 1859, it has been automated since 1994. The waters and adjoining seabed form part of the Needles Marine Conservation Zone and the Needles along with the shore and heath above are part of the Headon Warren and West High Down Site of Special Scientific Interest. The formation takes its name from a fourth needle-shaped pillar called Lot's Wife, which collapsed in a storm in 1764. The remaining rocks are not at all needle-like, but the name has stuck. The Needles were featured on the BBC Two TV programme ''Seven Natural Wonders'' (2005) as one of the wonders of Southern England. During Storm Eunice on 18 February ...
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