There are many distinctive and large prehistoric carvings at the Mesak Settafet escarpment, especially at Wadi Mathendous. The outcropping's exposed stones are covered in a dark
varnish or
patina containing minerals not currently present in the sandstone. The microns-thick patina of
iron and
manganese oxides were likely laid down on the rock when the area was much wetter, up to 3000 BC. The majority of the rock carvings in the area were probably first scratched then ground, likely with water, to create a purposeful finish. ==Rock tools==