From The First Systematic Geological Mapping of Algeria.
Rare and important early geological mapping of Algeria, focusing on the important coastal areas around Algiers and Oran, prepared for the first ever geological conference in Algiers in 1881.
Printed in Algiers by Adolphe Jourdan, the map shows 15 types of strata over some 100,000 kilometers of coastline and desert. This map uses a Depot de la Guerre base map from 1876. The geological detail on the map spans the Algerian coastline from Algiers to Oran, extending slightly past the two to Nemours (Ghazaouet) and Dellys. Inland, detail stretches to the Grand Erg Sea (El Erg), a vast sand plain with little exposure of strata.
The alpine mountain chains of northern Algeria are readily visible, with the Mesozoic and Cenozoic sediments and metamorphic rocks appearing at the north. These strata generally strike parallel to the coast, reflecting the collision of Europe and Africa.
History of Algerian Geological Mapping
The first large-scale geological map to be focused on a large portion of Algeria was Ville's Notice Mineralogique, which focused on the same area shown on the present map, albeit at a much lower resolution and encompassing only about half of the area. For the next twenty years, the geologists and surveyors cited on this map (Badynski, Nicaise, Pomel, Poyanne, Rocard, Rolland, Vattonne, and, of course, Ville himself) continued the mapping of the country.
By 1881, the work was ready for publication, greatly expanding the area covered by Ville's Notice Mineralogique. A second smaller map covering the area eastwards to the Tunisian border was also published by the same authors. These maps would be presented at the 1881 geological conference in Algiers - the first to be hosted in the country.
This is the first time we trace a complete example of this map as having appeared on the market.
Nicolas-Auguste Pomel studied at the Lycée de Clermont and earned his Licence ès sciences.
Pomel was conscripted into the army when he was prepared to enter the École des mines. He became a civil engineer after his discharge from the Army.
After the coup d'état of December 2, 1851 his Republican beliefs resulted in his deportation. He became a Garde des mines in Oran in 1866, and was promoted to the 1st class in 1872. From 1876 to 1882 he was member of the Senate (Oran division). In 1882 he was tasked with geological mapping of Algeria.
Pomel was also a prolific botanist, naming and describing many plant species and some genera as well. The genus Pomelia (Durando ex Pomel) from the family Apiaceae is named in his honor.
Justin Pouyanne entered the École Polytechnique in November 1853, and was admitted to the École des Mines in October 1855. He was appointed Engineer 3rd class in July 1859, and served in Algeria from April 1859. He would spend all his career in Algeria. At his own request he was assigned to the Tlemcen district in 1859.
Pouyanne was promoted to Engineer 2nd class in February 1863 and Engineer 1st class in February 1869. Pouyanne transferred to Algiers in 1873 as engineer. He was made a knight of the Legion of Honour in February 1878 and appointed Chief Engineer 2nd class in June 1878.
The Trans-Saharan expedition was appointed in 1879 by Charles de Freycinet, Minister of Public Works, to investigate construction of a railway across the Sahara. Three possible routes starting from Oran in the west, Algiers in the center and Constantine in the east were to be examined by three expeditions. The western expedition was led by Justin Pouyanne and the central one was led by the engineer Auguste Choisy and included Georges Rolland.
Pouyanne was promoted to Chief Engineer 1st class in July 1883. He was made an officer of the Legion of Honour on 13 July 1892. Later, rather than leave Algeria he turned down a promotion to General Engineer. In 1897 the post of Inspector General for Algeria, based in Algiers, was created especially for him in recognition of his great merit. He retired in September 1900, and gave up the direction of the geological map, which he had been working on for 20 years.