1911 Encyclopædia Britannica/Omalius d'Halloy, Jean Baptiste Julien d'
OMALIUS D’HALLOY, JEAN BAPTISTE JULIEN D’ (1783–1875), Belgian geologist, was born on the 16th of February 1783 at Liége, and educated firstly in that city and afterwards in Paris. While a youth he became interested in geology, and being of independent means he was able to devote his energies to geological researches. As early as 1808 he communicated to the Journal des mines a paper entitled Essai sur la geologie du Nord de la France. He became maire of Skeuvre in 1807, governor of the province of Namur in 1815, and from 1848 occupied a place in the Belgian senate. He was an active member of the Belgian Academy of Sciences from 1816, and served three times as president. He was likewise president of the Geological Society of France in 1852. In Belgium and the Rhine provinces he was one of the geological pioneers in determining the stratigraphy of the Carboniferous and other rocks. He studied also in detail the Tertiary deposits of the Paris Basin, and ascertained the extent of the Cretaceous and some of the older strata, which he for the first time clearly depicted on a map (1817). He was distinguished as an ethnologist, and when nearly ninety years of age he was chosen president of the Congress of Pre-historic Archaeology (Brussels, 1872). He died on the 15th of January 1875. His chief works were: Mémoires pour servir à la description géologique des Pays-Bas, de la France et de quelques contrées voisines (1828); Éléments de géologie (1831, 3rd ed. 1839); Abrégé de géologie (1853, 7th ed. 1862); Des races humaines, ou éléments d’ethnographie (5th ed., 1869).
Obituary by J. Gosselet, Bull. soc. géol. de France, ser. 3, vol. vi. (1878).