Espèces zonales d'Acritarches du Cambro-trémadocien de belgique et de l'Ardenne française [Zone species of acritarchs from the Cambro-Tremadocian of Belgium and the French Ardennes]

Nine acritarch zones are recognized in the Cambro-Tremadocian of Belgium and the French Ardennes. The author gives the main characteristics of these zones as well as an estimation of their position relative to the international chronostratigraphic scale. The zonation is based on the stratigraphic ranges of easily identifiable species, eight of which are new: Micrhystridium, lanceolatum, Priscogalea chevronensis, Leiosphaeridia fumiana, Lophosphaeridium bacilliferum, L. ? kryptoradiatum, Revinotesta microspinosa, Dictyotidium hasletianum and Polyedryxium ? pentagonale. Their description necessitated the establishment of a new genus: Revinotesta. The author proposes two new specific combinations and defines his concept of the genera Priscogalea, Cymatiogalea and Lophosphaeridium