[Musealia : Wax bust of Delaître, known as "La Taupe” (The Mole)]
Every month, Sorbonne University invites you to discover an object from its heritage collections. This month, discover "La Falunière de Grignon, a fossil site like no other".
What is the Lutetian?
The Lutetian is a stage of the Eocene epoch and refers to a period between 47.8 and 41.2 million years ago. Its name refers to the city of Lutetia, and it was Ernest Munier-Chalmas (1843-1903), successor to Edmond Hébert in the chair of geology at the Sorbonne, who, with Albert de Lapparent (1839-1908), was one of the first to use the outcrops of Paris and its surrounding region to symbolise this period of geological time.
However, it was not until the 1960s when Alphonse Blondeau (1922-2006), a future lecturer at the Pierre and Marie Curie University, was able to describe the reference sections of the Lutetian on two outcrops in the Oise (Saint-Leu d'Esserent and Saint-Vaast-les-Mello). While these sections clearly delineate the limits of the Lutetian stage, they are unfortunately rather lacking in fossils. The exceptionally well-preserved historical palaeontological sites of this age are therefore of great importance for understanding the vast Lutetian palaeobiodiversity.
La Falunière de Grignon
La Falunière de Grignon in the Yvelines is one of these exceptional sites. First reported by the naturalist Jacques-Tranquillain Féret in 1753, the falunière was made famous by Jean-Baptiste de Lamarck. Nearly 80% of the fossils described in his Mémoire sur les coquilles fossiles des environs de Paris, first published in 1802, are from Grignon, representing no less than 420 species.
Even today, at a time when La Falunière is the only one of the six original deposits to remain accessible, Grignon continues to be a source of scientific literature. Its extreme malacological richness (more than 810 species of molluscs have been recorded) and its exceptional quality of preservation (some shells show traces of residual colouration!) allows us to understand many geological, palaeoecological and paleoclimatic phenomena.
Since 2006, the site has been the subject of annual educational outings as part of the "Systematics, Evolution and Palaeontology" Master's programme at Sorbonne University and the National Museum of Natural History, during which many specimens are collected. An inventory of these specimens was carried out in 2021, prior to their entry into Sorbonne University's palaeontology collections, and during two internships carried out by Juliette Tessier-Supiot and Robin Piguet-Ruinet under the supervision of the BSU's Scientific Collections and Heritage Unit.
By Robin Piguet-Ruinet, intern at the Scientific and Special Collections Department, Sorbonne University Library.
Data sheet
- Name : Athleta spinosa Linnaeus 1758 ; Crassatella trigonata Lamarck 1805 ; Arca scapulina Lamarck 1805 ; Cirsochilus grignonensis Deshayes 1863 ; Ptychocerithium edulcoratum Cossmann 1889
- Type of object : fossils
- Date : Lutetian (40 million years)
- Place of storage : Sorbonne University's geoscientific collections
Bibliography
- MERLE D. (coord.) 2008. - Stratotype Lutétien. Muséum National d’Histoire naturelle, Paris ; Biotope, Mèze ; BRGM, Orléans, 288 p. (Patrimoine géologique ; 1).
- MERLE, D., AUBERGER, É. & Gély, J.-P. - Grignon (Lutétien, bassin de Paris) : « Terre sainte de la Science » paléontologique. Défendons la ! in Fossiles, n°27, 2016 : 5-18.
- SANDERS, M. T., MERLE, D. & VILLIER, L. 2015. - "The molluscs of the “Falunière” of Grignon (Middle Lutetian, Yvelines, France): quantifcation of lithification bias and its impact on the biodiversity assessment of the Middle Eocene of Western Europe." Geodiversitas 37 (3): 345-365.
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