STRUCTURE AND DYNAMIC OF A NEW BIOCONSTRU CTION OF MESOPHYLLUM LICHENOIDES (ELLIS) LEMOINE (CORALLINALES, RHODOPHYTA)

New infralittoral bioconcretions have been found in a fault of the roc ky inlet of Gameou (La Ciotat-French mediterranean coast). This pillar -shaped Coralligenous proceed from a ecomorphic form of Mesophyllum li chenoides (Ellis) Lemoine to a strong hydrodynamism and a dim illumina tion. It's building zip by the superposing of the thalli which are rei nforced by a biophysio-chemical magnesian calcite. This compact struct ure allowed us to determin the mean growth rate of 5 pillars by the ra diocarbon dating method. We obtained a value equal to 0,19 mm. year-1.