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A nummulite is a large lenticular fossil, characterized by its numerous coils, subdivided by septa into chambers. They are the shells of the fossil and present-day marine protozoan ''Nummulites'', a type of foraminiferan. Nummulites commonly vary in diameter from 1.3 cm (0.5 inches) to 5 cm (2 inches)〔Isquirth, Irwin Richard (2011). In ''The World Book Encyclopedia.'' print.〕 and are common in Eocene to Miocene marine rocks, particularly around southwest Asia and the Mediterranean (e.g. Eocene limestones from Egypt). Fossils up to 6 inches wide are found in the Middle Eocene rocks of Turkey.2 They are valuable as index fossils. The ancient Egyptians used nummulite shells as coins and the pyramids were constructed using limestone that contained nummulites.〔Isquirth, Irwin Richard (2011). In ''The World Book Encyclopedia.'' print.〕 It is not surprising then that the name "''Nummulites''" is a diminutive form of the Latin ''nummulus'' meaning "little coin", a reference to their shape. In 1913, naturalist Randolph Kirkpatrick published a book, ''The Nummulosphere: an account of the Organic Origin of so-called Igneous Rocks and Abyssal Red Clays'', proposing the unconventional theory that all rocks had been produced through the accumulation of forams such as ''Nummulites''. ==References== * 'Nummulite', ''Tiscali Dictionary of Animals'' (), retrieved 17 August 2004 *2. 'Biggest Microbes', ''Guinness World Records 2001'', p. 153. * http://paleopolis.rediris.es/cg/CG2006_M02/index.html 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nummulite」の詳細全文を読む スポンサード リンク
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