Discover France and Explore the Fossils and Geodiversity of the Charentese Purbeckian Sequence
- Wayne Munday
- 2 days ago
- 7 min read
The Charentese Purbeckian Sequence in the Charente region of south west France preserves a crucial record of the Jurassic–Cretaceous boundary around 145–139 million years ago. This sequence records a major marine regression across the northern Aquitaine Basin. Alternating gypsum, marlstone and limestone map out a paralic mosaic of hypersaline sebkha flats, restricted lagoons, estuaries and freshwater floodplains where storm-driven burial produced concentrated bonebeds and Konzentrat-Lagerstätten. Three key sites include Chassiron on Île d’Oléron, Cherves-de-Cognac and Angeac-Charente where each capture environmental transition. Together they yield diverse vertebrates including Iguanodon, stegosaurs, ornithomimosaurs, crocodylomorphs such as Goniopholis, bony fishes like Scheenstia and pycnodontiforms, plus abundant invertebrates, plants, trackways and coprolites. Rapid burial in fine sediments and storm surge deposition explains the exceptional preservation.
The Charente region of southwest France is a premier destination for visitors exploring the Charentese Purbeckian Sequence a string of world-class fossil sites from Île d’Oléron’s Chassiron headland to the Champblanc gypsum quarries at Cherves-de-Cognac and the Angeac-Charente bonebed near Angoulême.
This corridor combines palaeontology, vineyard terroir and river scenery: visitors can follow scenic driving and cycling routes along the Charente River to fossil museums, active excavations and Petite Champagne vineyards producing Cognac and Pineau des Charentes. Geological highlights include Purbeckian limestones, Berriasian bonebeds and evaporite gypsum exposures that reveal lagoons, tidal flats and floodplain ecosystems. This is a region of coastal attractions of wide Atlantic beaches and Marennes-Oléron oyster beds that complement inland natural sites such as the Antenne Valley Natura 2000 reserve, the turquoise quarry lakes of Guizengeard and Touvérac, and limestone caves at Montgaudier. With easy access from Angoulême TGV and well-marked heritage routes, the Charente offers a compact, visitor-friendly hub where deep-time geology, biodiversity and French rural culture meet, ideal for fossil hunters, birdwatchers and wine tourists alike.
The Cherves-de-Cognac Bonebed
Discover France and Explore the Fossils and Geodiversity of Cherves-de-Cognac in Nouvelle-Aquitaine - READ FULL BLOG
Cherves-de-Cognac, set within the rolling Charente countryside of southwest France, offers a rare window into Early Cretaceous ecosystems preserved along the Jurassic–Cretaceous boundary. As part of the Charentese Purbeckian Sequence, the site lies within the active Champblanc gypsum quarry, where continuous industrial excavation has revealed exquisitely preserved fossiliferous strata. These Berriasian-age deposits, dating to roughly 145–139 million years ago, record the early phases of the Cretaceous in remarkable sedimentological detail. Alternating layers of gypsum, dolomitic marlstone, laminated marls and fossil-rich limestone document a long-term regressive transition from hypersaline sebkha-style coastal flats and restricted lagoons to increasingly brackish estuarine channels, deltaic margins and freshwater lakes across the northern Aquitaine Basin.
Under arid to semi-arid climatic conditions, intense evaporation fostered gypsum precipitation in shallow basins, creating harsh, mineral-rich environments similar to those seen in the Purbeck Group of southern England and other Berriasian evaporite settings in Spain and Colombia. Yet these challenging habitats also acted as efficient preservational traps. Storm surges and high-energy pulses transported organisms from terrestrial, littoral and lagoonal settings into calmer basins, where rapid burial in fine sediments prevented decay and scavenging. Hummocky cross-stratification and thick bone-bearing horizons testify to repeated episodes of biological input, generating an unusually diverse vertebrate assemblage captured within a single, highly dynamic landscape.
The Cherves-de-Cognac bonebed preserves a thriving mosaic of ecological communities. Brackish lagoons supported abundant fish and reptiles, while progressively fresher lakes nurtured charophyte-rich plant communities, crustaceans, gastropods and potential nesting grounds marked by reptile eggshell fragments and well-preserved charophyte gyrogonites. Vertebrate fossils span large ornithopods such as Iguanodon, armoured Stegosauria, agile theropods like Dromaeosauroides, and a spectrum of turtles, lissamphibians, squamates and crocodylomorphs including Goniopholis and the neosuchian Pholidosaurus purbeckensis.
The fish fauna is particularly notable for its ecological breadth. Actinopterygian dominance is reflected in copious teeth representing diverse feeding strategies, from the crushing dentition of the ginglymodian Scheenstia mantelli to the durophagous pycnodontiforms equipped with cobble-like molar plates ideal for munching shelled prey. Episodic incursions of seawater introduced open-marine predators such as Caturus, Belonostomus and Thrissops, demonstrating that tidal or storm-driven connections with the Tethyan margins periodically enriched this confined basin.
For visitors, the geological richness of Cherves-de-Cognac pairs seamlessly with the cultural heritage of nearby Cognac, home to iconic houses like Hennessy, Rémy Martin and Martell. Vineyard tours, Charente River trails, and cycling routes such as La Flow Vélo offer scenic ways to explore the region. Nature enthusiasts can venture into the Antenne Valley Natura 2000 reserve, descend into limestone caves such as Montgaudier, or relax beside the turquoise, crystal-clear waters of Lac de Guizengeard and Touvérac, former quarries transformed into serene blue lakes. Together, the paleontological depth and tranquil landscapes of Charente create a destination where deep time, natural beauty and world-class Cognac come together in a uniquely immersive experience.
The Chassiron Bonebed
Discover France and Explore the Fossils and Geodiversity of Oléron Island in Charente-Maritime - READ FULL BLOG
Oléron Island, off France’s Atlantic coast in Charente-Maritime, preserves one of the richest Late Jurassic coastal records in western Europe. The Chassiron Bonebed, at the island’s northern headland beneath the iconic black-and-white Phare de Chassiron, is part of the Charentese Purbeckian Sequence and is encased within Early Tithonian Purbeck Beds. Deposited between roughly 146–140 million years ago, these limestones, shales and evaporites capture a paralic mosaic of lagoons, tidal flats, salt marshes and coastal swamps that developed along the western margin of the Tethyan seaway. The result is a Konzentrat-Lagerstätte: an unusually dense concentration of fossil material that preserves entire communities and ecological structure rather than soft tissues.
Sedimentology and taphonomy at Chassiron record repeated environmental oscillations driven by shifting sea level and episodic marine incursions. Laminated mudstones, evaporitic horizons and mudcracked track limestones reflect alternating brackish, freshwater and marginal-marine conditions. These fluctuating salinities created habitats for euryhaline organisms and permitted transient connections between the open Bay of Biscay and protected coastal basins. Plant detritus such as large accumulations of driftwood is identified as Agathoxylon and Brachyoxylon along with abundant charophyte gyrogonites, conifer fragments and fern remains, document extensive coastal forests that fed organic debris into lagoons and lakes.
The vertebrate assemblage at Chassiron is remarkable for its taxonomic breadth and ecological partitioning. Hybodontiform sharks dominate numerically; Parvodus and Planohybodus appear in abundance, their heterodont teeth and cephalic spines indicating versatile feeding strategies in fluctuating salinities. Actinopterygian fishes include diverse ginglymodians such as Scheenstia mantelli and Ionoscopiforms like Ionoscopus and Ophiopsis, alongside rarer pycnodonts and open-marine predators. Turtles, salamanders, frogs and albanerpetontids attest to stable freshwater niches, while a structured crocodyliform community ranges from longirostrine teleosaurids (Steneosaurus-type piscivores) to heavy-armoured goniopholidids such as Goniopholis and diminutive neosuchians probably analogous to Atoposaurids or Bernissartia. Dinosaur activity is recorded on tidal flats by tridactyl theropod tracks, sauropod impressions and thyreophoran traces, and Chassiron is notable as the first Jurassic mammal-bearing locality documented in France, preserving microvertebrate teeth and small jaw fragments.
Invertebrate and microfossil data reinforce the paralic interpretation. Neomiodontid bivalves, planorbid and provalvatid gastropods, and an ostracod fauna containing both euryhaline and freshwater taxa document repeated shifts between marine incursions and terrestrial input. Together, the molluscs and ostracods mirror classic Purbeck-type facies found across southern England and signal wide-ranging ecological links across the European epicontinental seas during the Tithonian.
Beyond its scientific importance, Chassiron sits within a living coastal landscape. Oléron Island is accessible via the Viaduc d’Oléron and offers wide Atlantic beaches, dune systems and sheltered eastern wetlands and oyster grounds. Although the Chassiron Bonebed itself is on private ground and not open to casual collecting, its fossils have broadened understanding of Late Jurassic paralic ecosystems and the ecological dynamics of the western Tethyan margin, making Chassiron a key locality for paleontologists studying the transition from Jurassic marine realms to the marginal continental environments that foreshadowed the Cretaceous.
The Angeac-Charente Bonebed
Discover France and Explore the Fossils and Geodiversity of Angeac-Charente in Nouvelle-Aquitaine - READ FULL BLOG
The Angeac-Charente Bonebed near Angoulême in Nouvelle-Aquitaine is one of France’s most scientifically important Early Cretaceous fossil sites, offering a rare window into a Berriasian-age wetland ecosystem preserved with exceptional detail. As the youngest locality within the Charentese Purbeckian Sequence alongside Chassiron and Cherves-de-Cognac it records the profound environmental shift across the Jurassic–Cretaceous boundary, when a major marine regression transformed former coastal settings of the Aquitaine Basin into expansive continental floodplains. Today, the site is managed by the National Museum of Natural History, whose summer excavations, guided tours and hands-on workshops allow visitors to observe active field research while learning how fossils form, decay and are prepared for scientific study. This blend of geoscience outreach and regional viticulture, set among Petite Champagne vineyards known for producing Cognac, Pineau des Charentes and fine eaux-de-vie, makes Angeac-Charente an exceptional destination for both fossil enthusiasts and travellers.
Geologically, the bonebed is preserved within lignitic or peaty clays exposed in gravel quarries near the Charente River. These low-energy floodplain sediments accumulated in a freshwater swamp environment where plants, invertebrates and vertebrates were rapidly buried with minimal disturbance. Since excavations began in 2010, researchers have recovered more than 7,000 identifiable fossils and tens of thousands of fragments, including articulated skeletons, track casts, plant remains, coprolites and soft-tissue-associated specimens. This remarkable preservation reflects stable freshwater conditions, evidenced by unionoid bivalves, algal remains and abundant fossil wood from cheirolepidiaceous and Agathoxylon-type conifers that flourished in a warm, subtropical climate.
During the Berriasian, Europe existed as a fragmented archipelago bordering the Tethys Ocean, its landscapes shaped by shallow seas, tropical humidity and shifting coastlines. Angeac-Charente captures this world with exceptional clarity. The vertebrate assemblage is dominated by ornithomimosaurs whose clustered distribution indicates a catastrophic mass-mortality event, possibly linked to flooding. These are accompanied by sauropod remains, including a massive two-metre femur, as well as stegosaurs, early iguanodontians and rare theropods related to megalosauroids and early tyrannosauroids. The site’s crocodilian fauna is especially revealing: species of Goniopholididae and Bernissartiidae preyed on freshwater turtles such as Pleurosternon bullockii, leaving distinctive bite marks and crushed carapaces that document predator–prey behaviour. Amphibians, turtles, small mammals and diverse invertebrates complete a rich wetland ecosystem.
Equally significant are the more than one hundred natural dinosaur track casts preserved in the clay, including large sauropod impressions and multiple Deltapodus-type tracks that suggest social behaviour among stegosaurs. Over 3,300 coprolites from herbivorous pellets to fish-rich carnivore droppings reconstruct a multi-layered food web, while termite coprolites and borings in conifer wood reveal active decomposition processes within the swamp.
Together, these fossils recreate a vivid “frozen scene” of Early Cretaceous life on the western Tethyan margin, where dinosaurs roamed in groups, crocodiles hunted along muddy channels and insects recycled fallen vegetation. For modern visitors, Angeac-Charente offers an immersive journey into deep time framed by the cultural heritage of the Charente Valley a place where world-class palaeontology and world-renowned Cognac share the same landscape.
