User:Neil Givens/Newspaper Rock

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The reason for the large concentration of the petroglyphs is unclear. One suggested explanation is that the rock was used as a place for communication through the petroglyphs between travelers.

The pictures at Newspaper Rock were inscribed into the dark coating on the rock, called desert varnish. Desert varnish is mainly made up (~70%) by clay materials, but gets its blackish color from iron and manganese oxide deposits that gradually form on exposed sandstone cliff faces owing to the action of rainfall and bacteria. The ancient artists produced the many types of figures and patterns by carefully chipping the coated rock surfaces with sharpened tools to remove the desert varnish and expose the lighter rock beneath. The older figures are themselves becoming darker in color as new varnish slowly develops.

The petroglyphs cover several styles, with symbols from later periods covering those from earlier styles. This suggests the art was developed over a large amount of time, and may mean the wall was a trail shrine from people moving through the area.

Depiction of Polydactyly
Many of the petroglyphs appear to be depicting polydactyly, the condition of having an extra toe or finger. In other Puebloan sites, burial remains with bifid metatarsals have been found near petroglyphs depicting polydactyly, suggesting that the pictures factually represent a real physical abnormality. One team of anthropologists excavated 96 skeletons from the nearby site of Pueblo Bonito and found that 3.1% of the skeletons had an extra toe on the right foot. This is a significantly higher rate of polydactyly than is seen in current Native American populations. There was evidence towards those with six toes being buried with items associated with higher social status, like an ornate bracelet, and turquoise. Polydactyl is also considered a moderately heritable condition, with 30-35% of those displaying the defect also having a close relative with polydactyl. This means that it may be possible to use polydactyl to reconstruct ancient Puebloan lineages.