Beginning with the Aptian and Albian the sea again gradually spread over the country and attained its maximum in the early part of the Senonian epoch, when once more the ancient massifs of the Central Plateau, Brittany and the Ardennes, alone rose above the waves.
The Senonian consists of a central facies with Micraster peini; a meridional facies with Ostrea; and a northern facies developed round Tunisia with large forms of Inoceramus and echinoids.
The Turonian is also sandy, but in most areas was not deposited, or has been denuded away during a local uplift that preceded Senonian times.
The Senonian series is represented by the White Limestone, a hardened chalk with flints, which is often glauconitic and conglomeratic at the base.
Four species of Dewalquea, a ranunculaceous genus allied to the hellebore, make their appearance in the Upper Senonian of Westphalia, other species occurring at Aix-la-Chapelle in deposits of about the same age.
The Senonian limestone itself, which rests in the extreme north on Trias or even on the schists, is often conglomeratic and glauconitic at the base, the pebbles being worn from the old metamorphic series.
There is a continuous transition between the Senonian and Danian, proving that the Algerian region did not participate in the immersion which occurred in Provence and in the Corbieres of southern France during the Danian epoch.
The Senonian strata have yielded 118 species, 21 of which are Cryptogams, 1 i Conifers, 5 Monocotyledons, 75 Dicotyledons.
Wanting Danian Upper Chalk Senonian Middle Chalk Turonian Lower Chalk Cenomanian Upper Green-sand Gault Albian Aptian Lower Green-sand Valenginian Urgonian Wealden Neocomian In the continental classification the deposits from the Gault downwards are grouped as Lower Cretaceous; but in Great Britain there is a strong break below the Gault and 'none above; and the Gault is therefore classed as Upper Cretaceous.