2.2.2. Mons Formation - Mo

Authors: Dewalque (1868), Robaszynski (1988b).

Description: the Mons limestone is a pale, marine limestone, friable or sometimes very coherent; it contains a very abundant neritic macrofauna. An erosional surface separates the Mons Fm from the Spiennes Chalk in the borehole of the stratotype. A clear superposition of the Mons limestone on the sediments of the Ciply Fm has never been demonstrated.

Stratotype: "Goffint" pit at Mons (cf. Cornet & Briart, 1865), "Coppée" pit at Mons (cf. Cornet & Briart, 1865; Robaszynski, 1981). Mons borehole (cf. Marlière, 1977). Sheet 45/7-8 (Mons - Givry). Co-ordinates: x = 123.10, y = 128.14, z = +56.8 m.

Area: the central part of the Mons Basin, only in boreholes.

Members: the formation is not subdivided into members.

Thickness: strongly fluctuating, from 15 to nearly 70 m.

Age: Middle and Late Danian.

Remarks: the formation is also discussed by Briart & Cornet (1870-1889), Cornet & Briart (1865), Maréchal (1993), Marlière (1977) and Robaszynski (1979, 1981).