Abstract
Rich assemblages of acid-resistant microfossils occur in intertidal sediment from the British Isles and are here reported, for the first time, to contain large numbers of dino-flagellate cysts. These cysts provide evidence to show that the distribution of certain dino-flagellate cysts is different from that of the motile stage, that the coastal distribution of cysts appears to be controlled by currents and that their occurrence within bays is possibly related to localized temperature and salinity conditions. Further, they present evidence that potential conditions for a red tide of Gonyaulax polyedra Stein may be present in the east Irish Sea.