(b. Cambrai, France, 19 April 1832; d. Lille, France, 20 March 1916)
Son of Alexandre Gosselet, a pharmacist in Landrecies, Gosselet lived until the age of eleven in the open countryside, enjoying a freedom interrupted only by the lessons given him by his aunt, who lived in the same house. He then studied at the Institution Courboulis in Landrecies and finally at the lycée in Douai, where he received his bachelier.
Gosselet enrolled at the École de Pharmacie in Paris and remained in the French capital to take the cours de candidature; he then returned to Landrecies for his practical training, which at that time required three years. He occupied himself during this period with the education of his sisters; it proved so much to his taste that he abandoned the career that his father had planned for him in favor of one in education.
He entered the collège of Quesnoy, a small town near Landrecies, as assistant teacher of mathematics and remained there while preparing for his licence, for which he took the examination in Paris. Although he was unanimously rejected by the jury, his talents were recognized by his examiners; among them was Constant Prévost. who offered him the position of préparateur of the geology course at the Sorbonne. He held this post for seven years, identifying, preparing, and cataloging specimens. Of the two teachers who formed his views, Constant Prévost and Edmond Hebert, the former enjoyed trying out theoretical views, while the latter was a strict empiricist. As Charles Barrais aptly observed, Prévost taught his students to soar before they could walk, and Hébert taught them to walk but to remain earthbound.
While in Paris, Gosselet visited the nearby quarries and construction sites, thereby acquiring his views on the parallelism of marine and lacustrine facies.
In 1857 Gosselet presented a detailed section of the quarries at Etroeungt, situated near Landrecies and the Belgian frontier. Here he observed strata forming the transition from the Devonian to the Carboniferous. They were characterized by a mixture of fossils. a finding that opposed accepted ideas of clearly demarcated boundaries between the stages. This study was a prelude to his important researches on primary formations, which he submitted for the doctorate in natural sciences. In 1860 Gosselet became a teacher of physics and chemistry at the lycée in Bordeaux. He left secondary teaching in 1864 to become assistant professor of natural history in the Faculty of Science at Poitiers and several months later became professor of geology at Lille. He also assisted the Service de la Carte Géologique de France, for which he made some surveys, and worked for the Service de la Carte Géologique de Belgique.
Gosselet profited from his stay at Bordeaux by studying the shell marls of Saucats and Léognan, as well as the freshwater limestones of northeast Aquitaine and the limestone of Blaye; but it was his appointment to Lille which allowed him to devote himself to the study of the region bounded on the east by the Rhine, on the west by the English Channel, on the north by the Yser, and on the south by Paris. He began with the ancient massifs of the Ardennes.
With the presentation of “L’Ardenne” to the Société Géologique du Nord, Gosselet outlined the principles upon which his deductions were based: the intervention of the paleontological evidence; the notion of the stratigraphic basin, that is, of a depression similar to that of our present seas and surrounded by continents; the important role of faults; and the synchronism of facies. The application of these rules led him to several famous discoveries. He established that two basins had existed since the Devonian: the basin of Dinant and the basin of Namur, separated by an ancient shore, a narrow strip of Silurian. These two basins were gradually filled in, independently and under different bathymetric conditions. Gosselet did not propose an absolute synchronism of the same fauna. His principle is based on the variations of the sediments and the faunal succession under the geographic condition of the area. For Gosselet the paleogeographic reconstruction of a region furnished the essential data for the solution of local stratigraphic problems. He changed considerably the legends of the geological maps of Belgium in particular.
The study of numerous deep boreholes led Gosselet to recognize the continuity of the folding in the two distinct geographic massifs of the Boulonnais and the Ardennes. The paleontological horizons of the Boulonnais were repeated in the same order at the northern flank of the Namur basin. Thus, the coalfields of the Boulonnais were located in the Westphalian, not, as had been thought, in the Lower Carboniferous.
Gosslet determined that the Ardennes was the result of a fold. Since his work, inclined and even horizontal faults have been considered, as well as the vertical ones. He saw that the basin of Dinant—the entire Ardennes—was mobilized by tangential forces and its northern side overthrust the north of Belgium. These studies guided the German Geological Service in the interpretation of the Eifel plateau.
Gosselet was still interested in the cenozoic and mesozoic eras in the geology of the north of France. He mentioned successive seas which have invaded the region from the Triassic to the present. He showed that there was little uniformity in the accumulation conditions of the chalk deposits and no relationship to white marine chalk deposits. Moreover, he confirmed the existence of stepped faults of the Cretaceous (or epi-Cretaceous) strata that must be surmounted in approaching the Paris basin. The relief of the topographic surfaces of the north of France owes its fundamental features to a system of post Cretaceous fractures. In Flanders these post Cretaceous faults had, moreover, been preceded by Post-Jurassic faults in Artois and Post-Carboniferous ones in the north. “Gosselet thus revealed the evolution of a great tectonic line along which the earth’s crust had contracted in a persistent and periodic manner since the beginning of time” (C. Barrois, p. 31).
Field studies and materials in historical archives led Gosselet to conclude that from the Tertiary to the present time, Flanders has been sinking at the foot of Artois in an uninterrupted but irregular movement. Gosselet was above all a field man whose observations gave rise to inspired hypotheses.
I. Original Works. Gosselet’s most important writings include Esquisse géologique du département du Nord et des contrées voisines, 2 pts. (Lille, 1871–1876); Esquisse géologique du Nord de la France et des contrées voisines, 4 pts. (Lille, 1880–1903); L’Ardenne (Paris, 1888); and “L’Ardenne,” in Annales de la Société géologique du Nord 16 (1889), 64–104.
II. Secondary Literature. On Gosselet or his work, see “Cinquantenaire scientifique de M. Jules Gosselet, 30 novembre 1902,” in, Annales de la Société géologique du Nord, 31 (1902), 157–296; Charles Barrois, “Jules Gosselet 1832–1916,” ibid, 44 (1919), 10–47, with portrait; and F. Stockmans, “Gosselet, Jules-Auguste, Alexandre,” in Biographie nationale publicée par l’Académie royale…de Belgique, XXXIV (Brussels, 1967), cols. 425–429.