Microfossiles a paroi organique de l'ypresien inferieur a quenast

Twohundred and fortyeight species of organic walled micro- fossils, with among them seven new species, were found in the Sands of Oostende-ter-Streep, the Clay of leper, the Sands of Mons-en-Pevele and the Clay of Merelbeke in the Belgian basin. The assemblages of the marine Ypresian deposits are rich and totally different from the very poor assemblages of the lagunar Landenian deposits. About one fourth of the species have been found, each of them, in a limited part of the sequence. Their distribution allows us to correlate Ypresian deposits of several localities in the Belgian basin with those from the reference profile of Kallo with a precision of about five to ten metres