The Todd River Dolomite (Amadeus Basin) and Mount Baldwin Formation (Georgina Basin) are a part of the Early Cambrian platform cover of the central Australian craton. Marine dolostones of these rock units preserve a limited archaeocyathan-radiocyathan fauna, including Aldanocyathus greeni Kruse sp. nov., Coscinocyathus bilateralis (Taylor), Dictyocyathus, Aruntacyathus toddi Kruse gen. et sp. nov. (Metacyathidae), and Radiocyathus minor (Bedford and Bedford). ?Aruntacyathus rossi Kruse sp. nov. and Beltanacyathus Bedford and Bedford are known traditionally from the Todd River Dolomite. On the basis of the common occurrence of elements of Faunal Assemblage No. 2 (Daily, 1956), the Todd River Dolomite and Mount Baldwin Formation can be correlated with the lower part of the Ajax and Wilkawillina Limestones of South Australia. The central Australian and corresponding South Australian archaeocyathan faunas appear to be coeval with those of the Atdabanian and possibly early Lenian stages of Siberia.