• La formation Jurassique superieur comprend deux ensembles lithologiques distincts:

•--a la base, un enseble volcano-sedimentaire contenant de rares Inocerames;

•--au-dessus, un enseble detritique compose essentiellement par des arenites tres fines qui contiennent la macrofaune. Elles sont noires, micacees, tres pyriteuses et contiennent de nombreux aspect tigre caracteristique. des niveaux intercalaires de shales noires, de litarenites volcanosedimentaires et de calcaires greseux sont subordonnes.

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•Dans les horizons fossiliferes, on note l'abondance de nodules spheriques, de taille centimetrique, siliceux ou arenitiques, plus rarement calcaires. Ces nodules sont generalement azoïque.

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•Translated to English:

•The Upper Jurassic formation includes two distinct lithological:

•- at the base, a volcano-sedimentary enseble containing rare inoceramids;

•- Above, a detrital enseble consists mainly of very fine arenites containing macrofauna. They are black, micaceous, very pyritic and contain many characteristic appearance tiger. Levels of intermediate black shales of litharenites volcano-sedimentary and sandy limestones are subordinate.

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•In the fossiliferous horizons, there is plenty of spherical nodules, centimetric, siliceous and detrital, more rarely limestone. These nodules are usually lacking fossils.