Evidence bearing on the type of environment represented by the track-bearing, cross-laminated Coconino sandstone of Permian age in northern Arizona has been obtained through a series of experiments. Using both reptiles and invertebrates an attempt has been made to develop in fine-grained sand, tracks that are comparable to those in the sandstone, thus demonstrating the conditions required for their development. Track variations due to differences in degree of sand slope, in moisture content of sand, and in direction of the animal's movement were observed and noted.