Embankment

The substrate where Les Monts, the hills here north of this street, are built can be clearly seen on the edge of Rue des Comtes de Robiano. Here you can see the calcareous, golden yellow tertiary sand. This is the Paleogene Brussels Formation and consists mainly of fine to medium calcareous sand with glauconite and sandstone banks. Those sandstone banks can be found on the hills of Les Monts. The Sands of Brussels are often mined as masonry sand.

This sand formation can also be found on lake to the north in the Hallerbos, Dworp, SInt-Genesius-Rode and Brussels (see map). We're on the western side of that formation here.

The formation was deposited in a narrow and long sea basin with tidal currents in the south-north direction. Numerous fossils were found in the Sands of Brussels. They point to an individual-rich but species-poor marine environment, close to the coast, in a subtropical climate. The Brussels Formation has an age transition Ypresian-Lutetian (about 50 million years old) and belongs to the Senne Group.

Dromos