Dinoflagellate cyst assemblages from Tertiary non-marine sediments from Australia are described, illustrated and compared with those from sediment immediately preceding the Eocene transgression in South Australia. The non-marine cyst types are quite distinct morphologically from those in the 'marginal marine' environment. Their diversity is low but they may dominate the acid insoluble microfossils. No acritarchs have been observed in any of the non-marine sediments. In contrast, assemblages from 'marginal marine' sediments include acritarchs and dinoflagellate cyst species that are common also to the assemblages recovered from sediments of the open marine environment. Low species diversity and relative frequency are the only factors that may be common to both types of assemblages.