Coconino Sandstone The sediments and the trace fossils of the Coconino Sandstone record the advance passage of a major eolian sand sea. Both invertebrate and vertebrate traces indicate that the substrate was, was for the most part, very dry though it was clear that light rainfall or dew periodically moistened the dune surfaces. Although we know that the erg was characterized by both simple and complex bedforms that apparently were oriented approximately transverse to the main direction of sand transport, we have much to learn about the distributions of the bedforms and the dynamics of the Coconino erg. Introduction The Early Permian Coconin