Trace fossils from a Middle Cambrian deltaic sequence, north Spain

An analysis of the lithofacies and trace fossils from a Middle Cambrian deltaic sequence in the Cantabrian Mountains northwest Spain indicates the importance of energy conditions as evidenced by bed thickness and the presence of sand mud alternations in determining the distribution of trace fossils. This facies control of trace fossils is particularly strong for trilobite tracks and U tubes. An analysis of Arenicolites and Diplocraterion demonstrates that the size of the trace fossil can be taken as an indicator of onshore offshore conditions. Thirteen ichnogenera are described including the new ichnospecies Monomorphichnus pectenensis, Rusophycus ramellensis and Teichichllus ovillus.