Abstract:

The charophyte assemblages of the Cretaceous and Paleogene of Hunan Province may be divided into 10 zones(or assemblages)in ascending order.1st zone:Perimneste ancora-Triclypella calcitrapa zone(the middle stageof the Early Cretaceous),represented by the Dongjing Formation of Hengyang Basin.2nd zone:Flabellochara hebeiensis zone(the middle-late stages of the Ear-ly Cretaceous),represented by the Qijiahe Formation of Dongting Basin.3rd zone:Atopochara trivolvis trivolvis zone(the late stage of the EarlyCretaceous),represented by the Mayang Formation of Yuanma Basin.4th zone:Atopochara trivolvis qidongensis zone(the late stage of theEarly Cretaceous),represented represened by the Huitangqiao Formationof Hengyang Basin.5th assemblage:Porochara anluensis-Latochara yuananensis assemblage(themiddle-late stage of the Late Cretaceous),represented by Daijiaping Forma-tion of Hengyang Basin.6th assemblage:Euaclistochara dongtingensis-Maedlerisphaera minuscula as- semblage(the late stage of Late Cretaceous),represented by the YanmatouFormation of Dongting Basin.7th assemblage:Grovesichara changzhouensis-Stephanochara breviovalis as-semblage(the Late Paleocene),represented by the Xinwan Formation of Dongting Basin.8th assemblage:Obtusochara elliptica-Peckichara longa assemblage(the Early Eocene),represented by the Yuanjiang Formation of Dongting Basin.9th assemblage:Obtusochara Jianglingensis-Gyrogona qianjiangica assem-blage(the Middle-Late Eocene),represented by the Hanshou Formation of Dongting Basin.10th assemblage:Maedlerisphaera chinensis-Charites xinhekouensis assem-blage(the Late Eocene-Early Oligocene),represented by the Xinhekou Forma-tion of Dongting Basin.The boundary between the Cretaceous and Paleogene,according to the evo-lution,distribution and property of charophyte assemblages,should be pro-perly placed between the 6th and 7th assemblages.