One of the fairly available ways in identifying and recognizing marine and continental rocks is to study the nature and feature of the sediments which consist of micropaleontclogy. When identifying the Holocene marine and continental strata of Taihu Lake, situated on the south of the Yangtze Delta, one should take in-to account the possibility of the allochthococnosis microfossils carried by the Yangtze flood tidal current to the studied area. Consequently, the thanatococnosis which appears in the Holocene rocks can not be considered as the only evidence of marine ones.