exfoliation in massive (unbedded) sandstone. Since the exfoliated planes are parallel to the shape of the canyon walls, it is likely that the exfoliation formed as rocks were eroded out of the canyon, releasing the load pressure that once confined the rocks.
rugose (or horn) coral with branching corals nest to it.
lungfish burrows. AN expert in such matters will travel with him to this site on his river trip in September.
Part II follows this in the next post.