Plenty of dinoflagellates and acritarchs are firstly discovered in theLate Cretaceous Dalanshan formation of Sanshui Basin

Guangdong Province.Two assemblages recognized in the Formation

from bottom to top

areas follows:1.The Palaeostomocystis-Compenia assemblage

in which pollen

spores and Pediastrum are predominat but with sparse plank tonic algaeindicating a near-shore transitional environment;2.The Parastrocysta-Api-culadinium assemblage.The content of phytoplankton in this assemblageis equal to

or much greater than

that of pollen and spores

and rich ingenera and species

whereas Pediastrum degenerated.Most of dinoflagellatesin the Formation are small in size.with thin outer membranes and sparseornaments

clear girdle and apex

obscure tabulates

archaeopyle is unseen

“nucleus”is present near the ventral surface.These features may indi-cate that the sediments were deposited in brackish water and the Late Cre-taceous transgression had some influence on this area.The depositionalenvironment of this assemblage might be favorable for the oil genesis.Five new genera are described in this paper

they are Parastrocysta

Apiculadinium

Belatudinium

Sanshuia

and Pseudoslephodinium

all together14 new species.