Early Cambrian marine sediments in the Arrowie Basin, South Australia, were deposited on a continental margin platform, and have been divided into five unconformity bounded depositional sequences and subsequences, ranging in age from basal Cambrian to early Toyonian. The Cambrian sediments are well exposed in the western part of the basin, but are concealed under Mesozoic to Quaternary cover in the east. There, in early 1976, a nearly complete buried Cambrian succession was intersected by drilling and fully cored in SADM Yalkalpo 2 stratigraphic well, and these sediments contain abundant trilobites, small skeletal fossils, archaeocyaths, and organic-walled microfossils. Four trilobite zones are recognised in the drill cores, ranging from late Atdabanian (Abadiella huoi Zone) to Toyonian (Pararaia janeae Zone). Two archaeocyathan zones (beds) also occur with the trilobites. Additionally, three acritarch assemblages are present, dominated by Skiagia. Continuous occurrences of the acritarchs Skiagia, Ceratophyton and Corollasphaeridium provide valuable evidence of evolutionary development, and are thus useful for biostratigraphic zonation in South Australian Cambrian sequences. New acritarch species or combinations found in Yalkalpo 2 and described herein include Baltisphaeridium bimacerium sp. nov., Ceratophyton circufuntum sp. nov., Ceratophyton dumufuntum sp. nov., Ceratophyton spinuconum sp. nov., Corollasphaeridium aliquolumum sp. nov., Corollasphaeridium opimolumum sp. nov., Veryhachium (Veryhachium) trisentium sp. nov., and Vulcanisphaera pseudofaveolata (Fridrichosone, 1971) comb. In addition, a modified diagnosis of Skiagia is presented.