摘要：

Footprints occur in the dune facies, both on foreset and bounding surfaces, and in the interdune deposits. , , , small and lepidosauromorphs/pterosaurs(?) occur on dune foreset surfaces. The remaining horizontally-bedded track-bearing sedimentary facies preserve , , and large . The correlation between facies and ichnotaxa has been attributed to the trackmakers' preference for particular environments, leading to the concept of "vertebrate ichnofacies". In this scenario, synapsids, crocodylomorphs, lepidosauromorphs/pterosaurs(?) and small dinosaurs were restricted in life to dune environments, while the larger dinosaurs were limited to playa environments. Instead, it is suggested here that the facies-taxon relationship reflects preservational bias, due to foot-substrate interactions and kinematic factors, rather than habitat preference. Only the tracks of small animals are likely to be preserved on foresets - the traces of larger animals will be obscured by grainflow and other sedimentological processes. In the playas, small tracks are not preserved. The scale of the algal features is of the same magnitude as the small footprints; this, combined with any subsequent diagenetic alteration, effectively obliterates all but the largest footprints.

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