Charles-Louis-Joseph-Xavier de la Vallée Poussin

Charles-Louis-Joseph-Xavier de la Vallée Poussin (6 April 1827, Namur – 15 March 1903, Brussels) was a Belgian geologist and mineralogist.

Appointed professor in 1863 on the recommendation of Omalius d'Halloy, he instigated the teaching of geology and mineralogy at the University of Louvain.

De la Vallée Poussin wrote publications on the microscopic study of the crystalline rocks of the Belgian and French Ardennes, several in collaboration with A.F.

He also wrote numerous notes on the Carboniferous limestones of the Ardennes and fixed the true stratigraphical relations of its beds and destroy Dupont's theory of lacunæ.

He studied the formation of the Valley of the Meuse; and wrote popularizing articles, which rank him with the first promoters of physical geography.