An ichnofossil assemblage from the Lower Carboniferous Snowy Plains Formation, Mansfield Basin, Australia
Abstract Continental strata of the Home Station Sandstone Member of the Snowy Plains Formation of the Mansfield Group, Avon Supergroup, Mansfield Basin in Victoria, Australia, contains diverse and abundant trace fossils, including domichnia, fodinichnia, pascichnia, and repichnia. The ichna are found in numerous beds in an approximately 28-m-thick unit referred to as Fish Hill, within the 250- to 500-m-thick Home Station Sandstone Member. The beds consist of alternating laminated mudstone and siltstone, thick-bedded ripple laminated sandstone, and thick-bedded massive sandstone with occasional discontinuous wavy lamination, trough cross-bedding and small-scale planar cross-bedding, interpreted as meandering river deposits. The trace-fossil assemblage includes Rusophycus , Cruziana , Palaeophycus , and Sagittichnus , a new ichnospecies of Fuersichnus and of Margaritichnus , and a new ichnotaxon Platicytes lioparadus . The geological and geographical distributions of many of these ichnotaxa are extended. Excellent examples of the compound nature of Cruziana and Rusophycus are illustrated. Ichnotaxa are herein grouped into a Rusophycus , Margaritichnus , and Cruziana ichnocoenoses, each identified according to their paleoenvironmental occurrence. This is the first detailed description on ichnofossils reported from Fish Hill, adding important palaeoenvironmental and palaeoecological information to what is previously known from these rocks based on vertebrate fossils.