Do not let anybody tell you that the early native dwellers were primitive people. I have seen photographs taken of this Great Gallery rock panel on the summer solstice, and it makes my neck hairs stand up. These men and women were astute observers of the natural world, and their sensitivity to celestial happenings puts me to shame.
On the first day of summer, the shadow of the cliff overhang comes to rest precisely on the shoulders of an unusual, one-of-a-kind anthropomorph who looks for all the world as if he is wearing giant shoulder pads. Standing in impressive contrast to the thin, elongated floating figures populating the panel, he’d weigh a quarter ton if he were real. On the solstice, he bears the weight of the shadow of summer — perfectly and precisely — on those oversized shoulders.
On the same day, at the other end of the gallery, a diagonal line of nine or ten pictograph bighorn sheep walk delicately along summer’s farthest shadow after it has crept along the cliff face. The artist placed them perfectly and calculatedly.
See this link if you’re interested in more about the fascinating field of archeoastronomy.