The Jura is internationally known for having given its name to the so-called 'Jurassic' period of the Secondary Era of our planet. The region was then covered with a shallow warm sea with biological and coral profusion where the sediments which later formed the Jura chain were deposited. The Jura gradually emerged during the Cretaceous before acquiring its current crescent shape following the thrust of the Alpine massif at the end of the Tertiary Era.