Pollen diagrams have been prepared of eight sections of Quaternary sediments from different localities on the coastal plain of British Guiana, and partly dated with the C 14 method. A Riss-Würm interglacial transgression, a Würm-glacial regression and a Holocene transgression have been established. The Würm-glacial vegetation on the place of the present coastal plain area was a poor grass-savanna type. The Holocene transgression at about 9500 B.P. is represented at 23 m. below present sea level and the maximum attained around 6500 B.P. when the relative sealevel was at least 2½ m. above that at present.