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Chalk

Chalk is a soft, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO3, it forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells shed from micro-organisms called coccolithophores. Flint is common as bands parallel to the bedding or as nodules embedded in chalk, it is derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is deposited around larger fossils such as Echinoidea which may be silicified. Chalk, as seen in Cretaceous deposits of Western Europe, is unusual among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones; this may indicate stable conditions over tens of millions of years. Chalk has greater resistance to weathering and slumping than the clays with which it is associated, thus forming tall, steep cliffs where chalk ridges meet the sea.

Chalk hills, known as chalk downland form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is well jointed it can hold a large volume of ground water, providing a natural reservoir that releases water through dry seasons. Chalk is mined from chalk deposits both above underground. Chalk mining boomed during the Industrial Revolution, due to the need for chalk products such as quicklime and bricks; some abandoned chalk mines remain tourist destinations due to their massive expanse and natural beauty. The Chalk Group is a European stratigraphic unit, it forms the famous White Cliffs of Dover in Kent, England, as well as their counterparts of the Cap Blanc Nez on the other side of the Dover Strait. The Champagne region of France is underlain by chalk deposits, which contain artificial caves used for wine storage; some of the highest chalk cliffs in the world occur at Jasmund National Park in Germany and at Møns Klint in Denmark – both once formed a single island.

Ninety million years ago what is now the chalk downland of Northern Europe was ooze accumulating at the bottom of a great sea. Chalk was one of the earliest rocks made up of microscopic particles to be studied under the microscope, when it was found to be composed entirely of coccoliths, their shells were made of calcite extracted from the rich seawater. As they died, a substantial layer built up over millions of years and, through the weight of overlying sediments became consolidated into rock. Earth movements related to the formation of the Alps raised these former sea-floor deposits above sea level; the chemical composition of chalk is calcium carbonate, with minor amounts of clay. It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are consolidated and compressed during diagenesis into chalk rock. Most people first encounter chalk in school where it refers to blackboard chalk, made of mineral chalk, since it crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be erased.

Blackboard chalk manufacturers now may use mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum. While gypsum-based blackboard chalk is the lowest cost to produce, thus used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, is marketed as "dustless chalk". Colored chalks, pastel chalks, sidewalk chalk, used to draw on sidewalks and driveways, are made of gypsum. Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water. In southeast England, deneholes are a notable example of ancient chalk pits; such bell pits may mark the sites of ancient flint mines, where the prime object was to remove flint nodules for stone tool manufacture. The surface remains at Cissbury are one such example, but the most famous is the extensive complex at Grimes Graves in Norfolk. Woodworking joints may be fitted by chalking one of the mating surfaces. A trial fit will leave a chalk mark on the high spots of the corresponding surface.

Chalk transferring to cover the complete surface indicates a good fit. Builder's putty mainly contains chalk as a filler in linseed oil. Chalk may be used for its properties as a base. In agriculture, chalk is used for raising pH in soils with high acidity; the most common forms are CaCO3 and CaO. Small doses of chalk can be used as an antacid. Additionally, the small particles of chalk make it a substance ideal for polishing. For example, toothpaste contains small amounts of chalk, which serves as a mild abrasive. Polishing chalk is chalk prepared with a controlled grain size, for fine polishing of metals. Chalk can be used as fingerprint powder. Several traditional uses of chalk have been replaced by other substances, although the word "chalk" is still applied to the usual replacements. Tailor's chalk is traditionally a hard chalk used to make temporary markings on cloth by tailors, it is now made of talc. Chalk was traditionally used in recreation. In field sports, such as tennis played on grass, powdered chalk was used to mark the boundary lines of the playing field or court.

If a ball hits the line, a cloud of chalk or pigment dust will

Toyota 92C-V

The Toyota 92C-V was a racing car built by Toyota as a Group C car, as a LMP car. It raced in the 24 Hours of Le Mans for three years, it took part in the final year of the All Japan Sports Prototype Championship during the 1992 season. Although with different names, the same two cars were used at the 24 Hours of Le Mans for three years, updated each year. A third chassis was used for the 1992 All Japan Sports Prototype Championship. Three cars were entered into the 1992 All Japan Sports Prototype Championship; the cars took part in every race. The 92C-V could not manage a win. Two cars were entered into the 1992 24 Hours of Le Mans, with the numbers #34 and #35; the cars qualified respectively. The 92C-Vs were the only cars in the Group C2 class to start the race. Both cars finished; the #34 car finished in 9th place overall. However, the #35 car managed to improve its position to 5th overall, it completed 6 laps behind the winner. The two cars were entered into the 1993 race; the cars were updated and renamed the Toyota 93C-V.

They had the numbers #22 and #25. Roland Ratzenberger driving the #22 car qualified 10th overall, while George Fouché driving the #25 car qualified 12th. Both cars completed the race, with Toyota again achieving a 1-2 finish in the C2 Category; the #22 car completed 363 laps, 12 laps behind the winning Peugeot 905. The #25 car was a further 5 laps behind. With the demise of Group C, Toyota further updated the cars and ran them as the Toyota 94C-V under the new LMP1 class for 1994; the two cars were entered with the numbers #1 and #4. Roland Ratzenberger was intended to be one of the drivers for the #1 car. However, he had suffered a fatal accident during the 1994 San Marino Grand Prix weekend. Eddie Irvine substituted for Ratzenberger. Mauro Martini's qualifying lap put the #1 car in 4th on the starting grid, while George Fouché qualified the #4 car into 8th. Both cars finished, for the third consecutive year, achieved a 1-2 finish in their class; the #1 car finished 2nd overall, 1 lap behind the winner.

The #4 car finished 4th overall, 16 laps behind the winner. The 94C-V participated in the 1994 1000 km of Suzuka, it retired from the race due to damage caused by an accident

Les Leggett

Leslie R. Leggett was an American football coach, his son Jack Leggett is the long-time head coach for the Clemson Tigers baseball team. After graduating from the University of Maine in 1951, Leggett served as a coach at Old Town High School in Old Town, Maine. In 1956, he served as an assistant football coach at Whitman College in Washington; the following season, he was hired as the head coach at Portland State University. At Portland State, he held the head coaching position for two seasons, from 1957 until 1958, his coaching record at Portland State was 6–11. He resigned from his position at Portland State in April 1959 to take over as head coach at Adrian. At Adrian College in Adrian, Michigan, he held the head coaching position for three seasons, from 1959 until 1961, his coaching record at Adrian was 9–14–1. Following his dismissal from Adrian, Leggett served as an assistant for the Vermont Catamounts. In addition to his career as a football coach, Leggett served as a coach for other college sports.

At Whitman he served as head baseball coach, at Adrian he served as head wrestling and track and field coach from 1960 to 1962. In 1962, Leggett established the swimming and diving program at Vermont and served as its head coach through the 1980 season. During his tenure as head coach the Catamounts had winning records in 16 of his 17 seasons. Les Leggett at Find a Grave