The family of Lamarck, as stated by H. Masson,[3] notwithstanding his northern and almost Germanic name of Chevalier de Lamarck, originated in the southwest of France. Though born at Bazentin, in old Picardy, it is not less true that he descended on the paternal side from an ancient house of Béarn, whose patrimony was very modest. This house was that of Monet.
Another genealogist, Baron C. de Cauna,[4] tells us that there is no doubt that the family of Monet in Bigorre[5] was divided. One of its representatives formed a branch in Picardy in the reign of Louis XIV. or later.
Lamarck’s grandfather, Philippe de Monet, “seigneur de Bazentin et autres lieux,” was also “chevalier de l’ordre royal et militaire de Saint-Louis, commandant pour le roi en la ville et château de Dinan, pensionnaire de sa majesté.”
The descendants of Philippe de Lamarck were, adds de Cauna, thus thrown into two branches, or at least two offshoots or stems (brisures), near Péronne. But the actual posterity of the Monet of Picardy was reduced to a single family, claiming back, with good reason, to a southern origin. One of its scions in the maternal line was a brilliant officer of the military marine and also son-in-law of a very distinguished naval officer.
The family of Monet was represented among the French nobility of 1789 by Messires de Monet de Caixon and de Monet de Saint-Martin. By marriage their grandson was connected with an honorable family of Montant, near Saint-Sever-Cap.
Another authority, the Abbé J. Dulac, has thrown additional light on the genealogy of the de Lamarck family, which, it may be seen, was for at least three centuries a military one.[6] The family of Monet, Seigneur de Saint-Martin et de Sombran, was maintained as a noble one by order of the Royal Council of State of June 20, 1678. He descended (I) from Bernard de Monet, esquire, captain of the château of Lourdes, who had as a son (II) Étienne de Monet, esquire, who, by contract dated August 15, 1543, married Marguerite de Sacaze. He was the father of (III) Pierre de Monet, esquire, “Seigneur d’Ast, en Béarn, guidon des gendarmes de la compagnie du roi de Navarre.” From him descended (IV) Étienne de Monet, esquire, second of the name, “Seigneur d’Ast et Lamarque, de Julos.” He was a captain by rank, and bought the estate of Saint-Martin in 1592. He married, in 1612, Jeanne de Lamarque, daughter of William de Lamarck, “Seigneur de Lamarque et de Bretaigne.” They had three children, the third of whom was Philippe, “chevalier de Saint-Louis, commandant du château de Dinan, Seigneur de Bazentin, en Picardy,” who, as we have already seen, was the father of the naturalist Lamarck, who lived from 1744 to 1829. The abbé relates that Philippe, the father of the naturalist, was born at Saint-Martin, in the midst of Bigorre, “in pleine Bigorre,” and he very neatly adds that “the Bigorrais have the right to claim for their land of flowers one of the glories of botany.”[7]
The name was at first variously spelled de Lamarque, de la Marck, or de Lamarck. He himself signed his name, when acting as secretary of the Assembly of Professors-administrative of the Museum of Natural History during the years of the First Republic, as plain Lamarck.
AUTOGRAPH OF LAMARCK, JANUARY 25, 1802