Comments on the paper “Reconnaissance of Upper Jurassic Morrison Formation ichnofossils, Rocky Mountain Region, USA: Paleoenvironmental, stratigraphic, and paleoclimatic significance of terrestrial and freshwater ichnocoenoses” by Stephen T. Hasiotis

Hasiotis (2004) has described and interpreted a relatively diverse and potentially very interesting ichnofauna from the Upper Jurassic Morrison Formation of the western United States. An effort was made by the author to bring the data to the reader, but, in our opinion, his analysis is seriously flawed and the resulting discussion and conclusions are not sufficiently supported by data. The unsupported ichnotaxonomic treatment and attributions of trace fossils to their supposed producers throughout Section 4 (Ichnology) undermines the 23 pages of discussions and conclusions. We believe that the contribution contains several problems that would deserve a critical and detailed analysis, which regrettably cannot be accomplished herein because of editorial restrictions. Only salient points are addressed herein.