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International audienceHere, we report flint nodules bearing fossil plant inclusions from the early Cenoma- nian of the Font-de-Benon sand quarry, between the villages of Archingeay and Les Nouillers, Charente-Maritime, western France. The broken-open surfaces of these dense siliceous rocks only partly show the whole diversity, which is established using a non-destructive, multi-scale approach based on propagation phase-contrast X-ray synchrotron microtomography. The conifer genera Brachyphyllum, Frenelopsis, Gein- itzia, and Glenrosa have three-dimensional preservation, and vegetative and reproduc- tive organs are in connection in some cases. The flint nodules formed by silicification of Cenomanian sediments, probably as a result of an intensive period of soil alteration and leaching under warm and wet climate during the Eocene. Although the time was long between the Cenomanian sedimentation and the Eocene silicification, the fossil plants show three-dimensional external morphology. These mineralizations are inter- preted as fine silica microcrystallization over the cell walls and thus are examples of late silica permineralization. The association of foraminifers, echinoids, sponge spicules, and conifers suggests that the Cenomanian sediments were deposited in a coastal and open to the sea palaeoenvironment, near a conifer-dominated mangrove

We report exceptionally well-preserved plant remains ascribed to the extinct conifer Glenrosa J. Watson et H.L. Fisher emend. V. Srinivasan inside silica-rich nodules from the Cenomanian of the Font-de-Benon quarry, Charente-Maritime, western France. Remains are preserved in three dimensions and mainly consist of fragmented leafy axes. Pollen cones of this conifer are for the first time reported and in some cases remain connected to leafy stems. Histology of Glenrosa has not previously been observed; here, most of internal tissues and cells are well-preserved and allow us to describe a new species, Glenrosa carentonensis sp. nov., using propagation phase-contrast X-ray synchrotron microtomography, a non-destructive technique. Leafy axes consist of characteristic helically arranged leaves bearing stomatal crypts. Glenrosa carentonensis sp. nov. differs from the other described species in developing a phyllotaxy 8/21, claw-shaped leaves, a thicker cuticle, a higher number of papillae and stomata per crypt. Pollen cones consist of peltate, helically arranged microsporophylls, each of them bearing 6–7 pollen sacs. The new high resolution tomographic approach tested here allows virtual palaeohistology on plants included inside a dense rock to be made. Most tissues of Glenrosa carentonensis sp. nov. are described. Lithological and palaeontological data combined with xerophytic features of Glenrosa carentonensis sp. nov. suggest that this conifer has been adapted to survive in harsh and instable environments such as coastal area exposed to hot, dry conditions.

Lower Cenomanian paralic facies outcrop widely on Aix Island (Charente-Maritime, France). Since the beginning of the 19th century, there has been repeated

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