After the mid-Holocene(6

000—7

000 years B.P.)

sea invaded Zhujiang (PearlRiver) Delta

then retreated gradually.However

the transgression limits in Gua-ngzhou-Huaxian Plain

lying to the northwest of Guangzhou City

was not ascer-tained yet.In 1985

a layer of dark-grey clay or silty clay was discovered on the Plain.In this layer

besides terrestial fossils such as little pieces and seeds of plants

there are a large number of marine micro-fossils including planktons and benthos.Three conclusions are offered:1.This layer of clay or silty clay consisting of marine micro-fossils is a marinelayer.2.This layer distributes south to Yahu-Qishan-Xinhua-Longkou.Therefore

thatline should be the limits of Holocene transgression in Guangzhou-Huaxian Plain.3.This layer exists in 2-3m above sea level.Since the Plain submerged gener-ally at the rate of 0.59mm yearly during Holocene

this layer should have formed3—4m above mean sea level.It indicates that there is surely a high sea level inZhujiang delta in holocene.