Abstract:

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.