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MUSCHELKALK

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Originally appearing in Volume V19, Page 44 of the 1911 Encyclopedia Britannica.
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MUSCHELKALK , in See also:

geology, the See also:middle member of the See also:German Trias. It consists of a See also:series of calcareous, marly and dolomitic beds which See also:lie conformably between the See also:Bunter and See also:Keuper formations. The name Muschelkalk (Fr., calcaire coquillier; conchylien, formation of D'See also:Orbigny) indicates a characteristic feature in this series, viz. the frequent occurrence of lenticular See also:banks composed of fossil shells, remarkable in the midst of a singularly barren See also:group. In its typical See also:form the Muschelkalk is practically restricted to the German region and its immediate neighbourhood; it is found in Thuringia, Harz, See also:Franconia, See also:Hesse, See also:Swabia, and the See also:Saar and See also:Alsace districts. Northward it extends into See also:Silesia, See also:Poland and See also:Heligoland. Representatives are found in the See also:Alps, See also:west and See also:south of the See also:Vosges, in See also:Moravia, near See also:Toulon and See also:Montpellier, in See also:Spain and See also:Sardinia; in See also:Rumania, Bosnia, See also:Dalmatia, and beyond this into See also:Asia in the Himalayas, See also:China, See also:Australia, See also:California, and in See also:North See also:Africa (See also:Constantine). From the nature of the deposits, as well as from the impoverished See also:fauna, the Muschelkalk of the type See also:area was probably laid down within a See also:land-locked See also:sea which, in the earlier portion of its existence, had only imperfect communications with the more open See also:waters of the See also:period. The more remote representatives of the formation were of course deposited in diverse conditions, and are only to be correlated through the presence of some of the Muschelkalk fossils. In the " German " area the Muschelkalk is from 250-350 ft. thick;' it is readily divisible into three See also:groups, of which the upper and See also:lower are See also:pale thin-bedded limestones with greenish-See also:grey marls, the middle group being ° mainly composed of gypsiferous and saliniferous marls with See also:dolomite. The Lower Muschelkalk consists, from below upwards, of the following rocks, the ochreous Wellen Dolomit, lower Wellen See also:Kalk, upper Wellen Kalk (so called on See also:account of the wavy See also:character of the bedding) with beds of " Schaumkalk " (a porous cellular See also:lime-See also:stone), and Oolite and the See also:Orbicularis beds (with Myophoria orbicularis). In the Saar and Alsace districts and north See also:Eifel, these beds take on a sandy aspect, the " Muschelsandstein." The Middle Muschelkalk or See also:Anhydrite group, as already indicated, consists mainly of marls and See also:dolomites with beds of anhydrite, See also:gypsum and See also:salt. The salt beds are worked at See also:Hall, Friedrichshall, See also:Heilbronn, See also:Stettin and See also:Erfurt.

It is from this See also:

division that many of the See also:mineral springs of Thuringia and south See also:Germany obtain their saline contents. The cellular nature of much of the dolomite has given rise to the See also:term " Zellendolomit." The Upper Muschelkalk (Hauptmuschelkalk, Friedrichshallkalk of von See also:Alberti) consists of See also:regular beds of Shelly See also:limestone alternating with beds of See also:marl. The lower portion or " Trochitenkalk " is often composed entirely of the fragmentary stems of Encrinus liliiformis; higher up come the " Nodosus " beds with Ceratites compressus, C. nodosus, and C. semipartitus in ascending See also:order. In Swabia and Franconia the highest beds are platy dolomites with Tringonodus Sandergensis and the crustacean Bairdia. Stylolites are See also:common in all the Muschelkalk limestones.

End of Article: MUSCHELKALK

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