3.13 Longwy Formation - LGW

Authors: Dumont, 1842; Boulvain et al. (2001).

Description: Orange yellow sandy limestone, followed by shelly limestone with locally conglomeratic layers with bioclastic limestone clasts. The base of the formation corresponds to the first limestone deposit superposed on Mont-Saint-Martin or, towards the west, on Grandcourt Formation. Its top coincides with the base of the "Marnes de Longwy".

Stratotype: Old quarries near the village of Tellancourt and road Ruette-Tellancourt, close to the French border.

Area and thickness: Longwy Formation crops out in the extreme south of Belgian Lorraine and the north-east of French Lorraine. The formation is about 50 m thick in the eastern area. Its thickness gradually thins towards the west, with no possibility of giving any value.

Age: Longwy Formation is dated from Lower Bajocian Hyperlioceras discites Zone to Stephanoceras humphriesianum Zone (Maubeuge, 1951, 1954).