The large, extinct, benthonic foraminifera Lepidocyclina, which has "tropical" affinities, has been found at two localities in the Nullarbor Limestone that outcrops on the eastern margin of the Eucla Basin. The species is apparently the usual, variable, South Australian species L. howchini Chapman and Crespin. At Seven Mile Swamps, the L. howchini zone is only about 0.2 m thick. Specimens here are rare and small, only 1-2 mm in diameter. At Lake Tallacootra, 70 km to the north-west, the zone is about 1 m thick and specimens are rare to frequent, 1-11 mm diameter, the larger individuals being microspheric, others megalospheric. At both localities the zone lies within a metre or two of the local base of the Nullarbor Limestone, and is more bryozoal than is usual for this formation. There is no reason to doubt that the zone here is a time-correlative of the L. howchini zone in the Saint Vincent and Murray basins, and represents a regional transgressive / warm water mass climatic episode of early Middle Miocene age.