Beachrocks like those in Haishan Island’s “beachrock field” are rarely found elsewhere. They contain typical cement-aragonite. The assemblages of foraminifera and ostracods show that they are typical littoral sediments, the middle and the lower beds of beachrocks being formed in the desalinized seawater, the upper bed in normal seawater. At least four coastal elevations and subsidences have occurred since Late Holocene. The amplitude of the last three subsidences increased each time and the sea coasts receded. Active elevation has been predominant since 600 years B.P.Periodical coastal elevation and subsidence in Fujian and Guangdong has been occurring for the past several thousand years. Each period was 500 years, 250 years of subsidence, 250 years of elevation. The containers of typical cement-aragonite. The assemblages of foraminifera and ostracods show that they are typical littoral sediments, the middle and the lower beds of beachrocks being formed in the The elevation of the last three subsidences increased each time and the sea coasts receded. Active elevation has been predominant since 600 years BPPeriodical coastal elevation and subsidence in Fujian and Guangdong has been occurring for the past several thousand years. Each period was 500 years, 250 years of subsidence, 250 years of elevation.