purpose of this comment is to question the organicnature of the material described by Retallack (2011) as‘problematic megafossils’ from the Moodlatana and Balc-oracana Formations, Lake Frome Group of the FlindersRanges, South Australia.By way of introduction, we note that there is a consider-able history of structures described from sedimentary rocksas fossils that do not stand up to scrutiny (Hofmann 1971,1992, 2005). The literature is replete with what Hofmann(1992) regarded as dubiofossils. The onus should always beon the author to demonstrate biological origins.Retallack (2011, p.1223) in discussing the need to nameproblematic fossils states that ‘Vendobiota were informallynoted by Mawson (1938, p. 259) as ‘fossil impressionsresembling brachiopod or bivalve form’, but formaldescription of five species by Sprigg (1947) was neededbefore their global distribution and importance as Ediaca-ran fossils could be appreciated (Fedonkin et al. 2007).’This is misleading because Mawson’s complete sentence is‘Fossil impressions resembling brachiopod or bivalve form,but probably merely impressions of clay galls’. Mawsonwas in fact describing a section through what would nowbe termed the Ediacaran Rawnsley Quartzite, from about1.6 km north of Parachilna Creek and about 50 km to thesouth east of where Sprigg (1947) initially found the Edia-cara biota near Ediacara in the Rawnsley Quartzite.The sedimentary rocks of the Lake Frome Group are ofCambrian Series 2, Stage 4 and Cambrian Series 3, Stage 5(early late to early middle Cambrian) in age and includefacies with recognisable body and trace fossils (Jago et al.2010). These formations represent the later stages of sedi-mentation in what has been referred to as the AdelaideGeosyncline (Sprigg 1952; Thomson 1969, 1970), AdelaideFold Belt (von der Borch 1980) or Adelaide Rift Complex(Veevers et al. 1997). Given that the Moodlatana Forma-tion includes both marginal marine and terrestrial units,palaeosol facies such as those described by Retallack(2008) cannot be ruled out. However, claims of fossilswithin palaeosols require very close scrutiny if onlybecause such claims are difficult to verify in palaeosols ofany age. Rocks of the Australian continent preserve one ofthe longest and most complex records of weathering andregolith history of any continent because the Australiancontinent has not suffered significant glacial erosion sincethe Early Permian (Crowell and Frakes 1971), nor has thecontinent suffered significant orogenic activity in post-Permian eras. Consequently, the weathering profile canextend up to >100 m deep for pre-Mesozoic rocks (Anand2005). In this context, distinguishing body fossils oflichens, fungi or even bacterial mats in Cambrian palaeo-sols would require exceptional evidence, given the paucityof evidence of fossils other than vascular plants in palaeo-sols of younger age. At the very least, we would expect tosee numerous specimens of consistent morphology in thesuite of material described by Retallack (2011) and lodgedin the South Australian Museum.Diagnoses should enable the reader to distinguish thedescribed taxa. The author should be able to demonstratea clear distinction between the putative fossil and the sed-imentary textures of the rock samples as well as theweathering textures in the sample outcrop. We wouldexpect the author to demonstrate that the weathering tex-tures were indeed derived exclusively from the purportedpalaeo-weathering effects implied by the claim of a palae-osol. The only reliable method of doing this in the con-text of Australia’s complex weathering history is toidentify both the palaeosol facies and the fossils, inborehole samples from depths below the local weathering