I took my Persian to my homeland this past week. While there, I visited this historic site that has some modest "petroglyphs" (cave pictures from ancients).
First a warmup
Here you can see the "Ghost Cave" in the background...more on that later.
The area used to be the lands of the Crow Indians. It is said they avoided the area due to there being no means of escape if they got cornered by their enemies.
If you look closely in this picture you can see round stone "ball" areas about halfway down the cliff. These were caused when the ancient sea bed that formed this sandstone formed around small sticks or other debris. They are important as when they fall out of the cliff they start the caves. They are called concretions.
Ghost cave and concretions...a different angle.
more to come...