Abstract: The fossil described-Daphnia sp. ephippium in this paper was collected from the 2nd and the 3rd members of the Hetaoyuan Formation at Nanyang, Biyang and Wuyang Depressions in Southwest and Central Henan Province. It is the first time that fossil ephippia of Cladocera rive discovered in this area, From palaeontological and palaeoecological studies of these fossils, three conclesions of their significance to petroleum geology are drawn by the writers: 1 .The fossil of ephippiurn of Cladocera is good W dicator for determing sedimentary facies; 2. The strata containing abundant cladoceran ephippia belong to seasonal sediments; 3 .The strata with numerous cladoc:eran ephippia give audio-visual information of faia-ly good souce rock.

摘要： 本文记述了河南省西南部和中部的南阳、泌阳和舞阳三凹陷下第三系核桃园组二、三段中所产的枝角类卵鞍化石Daphnia sp.,ephippium枝角类卵按化石在该区尚属首次发现,因此讨沦了它对该区石油地质的意义,经初步归纳有三点认识:1.枝角类卵鞍化石是确定沉积招的良好指示物;2.含枝角类卵鞍化石的岩层属季节性沉积;3.含众多枝角类卵鞍化石的岩层是良好生油岩的直观信息。