Maestrichtian Stage
Maestrichtian Stage
(named after the city of Maastricht, the Netherlands), the sixth, next to last, stage of the Upper Cretaceous system (period). It was first identified in 1849 by the Belgian geologist A.-H. Dumont. The type occurrence on the slopes of St. Pierre mountain is composed of shallow-water organogenic-detrital limestones that correspond to the top of the stage only. Fossils of ammonites, belemnites, foraminifera, sea urchins, and other organisms are very important for a detailed stratigraphic division of the stage. In the USSR the Maestrichtian stage is extensively distributed and is represented by various types of rock of both marine and continental origin.