Le Naturaliste Vendéen, Numéro 3 (2003)
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On the intertidal zone of Le Veillon at Talmond-Saint-Hilaire (Vendée, France), in 1963 Gilbert Bessonnat discovered traces of vertebrate footprints in a Hettangian formation. On March 28th & 29th, at this site a study session was held on the theme: "sites with vertebrate footprints on the Triassic-Jurassic limit". Palæontologists, palæobotanists, sedimentologists, hydrologists, scientific historians and naturalists compared their results and projected further research. This exceptional Vendée heritage site is to be protected and developed.
The region of Talmont-Saint-Hilaire (Vendée, France), located at the contact between the Armorican Massif, the Aquitanian Basin and the Atlantic Ocean, has been studied by many geologists and geographers, over the last three centuries. In the years 1780, silver was mined from the sulphide-bearing ore that occurs at the base of the Jurassic limestones. The stratigraphy of the latter sediments, as well as their relationship with the hercynian basement, was investigated during the 19th and 20th centuries, mainly by Rivière, the author of the first geological map of the area (1838), Cossmann, Vasseur, Péneau, Ters and Butel. As for Gabilly, he considered the anse Saint-Nicolas as a para-stratotype of the Toarcian. A few Authors, mainly Bocquier and Ters, also studied the evolution of the Atlantic coast during Quaternary. They evidenced remnants of several surfaces fashioned by marine abrasion, the age of which was constrained by archaeological studies. In 1963, Gilbert Bessonnat discovered dinosaur footprints, which, however, had already been observed by Bocquier in the years 1930. Montenat and Lapparent studied the occurrence, which proved to be one of the richest in Europe.
In the Talmondais (Vendée) the Hettangian sedimentation locally begins with fluviatil clastic deposits prior to the deposition of shallow marine carbonates. These clastics, including the footprint-bearing beds of Le Veillon (south of Talmont- Saint-Hilaire) are subject to important and frequent variations in thickness. Drilling and geophysic data indicate a tectonic control of these variations. A fault-block pattern is proposed. At a small scale, it gives an illustration of the extensional tectonic processes related to the evolution of the Biscay rift during the early Liassic.
Clastic deposits related to alluvial and estuarine environments sedimented during the early Liassic in the Veillon area (south of Talmont-Saint-Hilaire, Vendée, France). A reptile fauna including various taxa, just known by innumerable footprints, lived in that environment, in rather hot and dry climatic conditions.
One of the remaining French otter populations lives on Noirmoutier island where the marine environment offers food resources. A study of the otters' diets will prove if these resources are used or not.
In 1869 Tacite Letourneux described a new species of gasteropod, Valvata bourguignati, in a spring in south-east Vendée. The name of this new species was later considered to be synonymous with Neohoratia globulina. Recent samplings in the Locus typicus have permitted the revision of this taxon, now named Islamia moquiniana.
It has been forty years since the Jurassic site of Veillon in Talmont-Saint-Hilaire (Vendée, France), where footprints of vertebrates were found, was plundered. This outstanding site belonging to Vendée's geological patrimony needs to be preserved and developed. Some footprints from Veillon are displayed in the collections of about thirty public institutions and six museums.
A micro-crustacean has recently been discovered in Vendée. It is an Ostracod living in temporary bodies of slightly brackish or fresh water. From the Cyprididae family, Cypris bispinosa is a crustacean whose presence in France is only known from eight countess. It is however one of our largest ostracods, and the lateral spine fixed on each side of its carapace make the species easily recognisable with a lens.
Discovery of a single example of Mirror Orchid (Ophrys speculum) in the coastal forest of Longeville-sur-Mer, in southern Vendée. This orchid, hitherto unknown in Vendée, is very rare in France.
Tandonia rustica (Millet 1843) (Mollusca : Gastropoda), nouvelle espèce de limace pour la Vendée
(2003)
The slug Tandonia rustica has recently been discovered in the forest of Mervent, in Vendée. After a brief description of the site where the gastropod was found, the author describes the biology, ethology and distribution in France of this species.