Geological wall of Géromont, Geological monument in Comblain-au-Pont, Belgium.

The Geological Wall of Géromont is a monumental stratigraphic scale built from Walloon quarry rocks, running 54 metres along the southern slope of the Ourthe valley north of Comblain-la-Tour, in Comblain-au-Pont. It rises from a base of about 22 metres at 198 m altitude to a top of about 3 metres at 220 m, inclined at roughly 40%. Each metre of dry-stone wall, some fifty centimetres thick, stands for ten million years, from Cambrian quartzites and phyllades at the bottom to Quaternary deposits at the top, with one layer of Quenast porphyry among the sedimentary rocks.

The wall was conceived in 2004, when stone sculptor Paolo Gasparotto met Camille Ek, a geology professor at the University of Liège. It was built on the slope of an old underground Famennian sandstone quarry at Géromont, near Comblain-la-Tour, using rocks from Walloon quarries. Since 2016 the non-profit Les découvertes de Comblain has managed the work, still being completed in 2022.

The wall was conceived in 2004 by stone sculptor Paolo Gasparotto and Camille Ek, a geology professor at the University of Liège. Since 2016 the non-profit Les découvertes de Comblain has managed and guided this educational work, built with volunteers and quarry companies. Nearby stands the Centre d'interprétation de la chauve-souris, as the old underground quarries shelter many bats.

The wall stands on a south-facing slope near the spoil heaps of an abandoned underground sandstone quarry, north of Comblain-la-Tour in the hamlet of Géromont. The slope is about 40 percent, rising from a base at 198 m to a top at 220 m, so wear shoes with grip. The nearby Centre d'interprétation de la chauve-souris marks the area; the Ourthe valley lies below.

Only one layer is igneous: porphyry from the Quenast quarries in Walloon Brabant, representing the Silurian. Crushed, this abrasion-resistant rock supplied ballast for Belgian railways and aggregate for asphalt roads, and its paving stones once surfaced streets across the country.