Regular readers of this blog may recall that last summer I was in the southwestern US studying Permian sandstones with John Whitmore and Ray Strom. One of the places we visited was Natural Bridges National Monument in Utah where we examined the Cedar Mesa Sandstone. Our hike took us down to Kachina Bridge where we sat in the welcome shade and ate lunch (see photo left).
While we were there we also had the opportunity to examine the Native American rock paintings and petroglyphs, including one that has been featured in several creationist books and on websites as a putative representation of a sauropod dinosaur (see photo below). This particular petroglyph is displayed on a plaque at the Creation Museum in Petersburg, Kentucky, and one creationist, Doug Sharp, has suggested that other petroglyphs at the site also depict dinosaurs. These petroglyphs have been cited as evidence supporting the young-age creationist claim that humans and dinosaurs were contemporaneous.
However, a new paper by Phil Senter and Sally Cole in Palaeontologia Electronica casts doubt on the dinosaurian nature of these petroglyphs. Despite the interest that the sauropod image (“Dinosaur 1″), in particular, has generated, the authors point out that a detailed description has not previously been published:
This lack of research is understandable, because it is approximately 2 m above the head of the average observer on a nearly vertical surface, surrounded by rough and extremely steep terrain that discourages the carrying of a ladder, about an hour by foot from the nearest road.
Senter and Cole sought to rectify this with careful naked eye, binocular and telephoto lens examinations of the petroglyphs said to show dinosaurs under a range of lighting conditions. The abstract of their paper sums up their conclusions:
Examination reveals that the “neck” and “back” of Dinosaur 1 are a composite of two separate petroglyphs, and its “legs” are a natural mud or mineral stain. A second alleged sauropod petroglyph is a mere mud stain. The other two alleged dinosaur petroglyphs are human-made, but neither depicts an animal. The four Kachina Bridge “dinosaurs” are illusions produced by pareidolia.
The arguments seem persuasive to me, and my own photo above (click on it for a larger version) seems to confirm Senter and Cole’s claim that the sauropod “tail” is not actually connected to the rest of the body. However, you can make up your own mind once you’ve read the paper.
And, yes, this paper is co-authored by the same Phil Senter who recently published a statistical baraminology study in the Journal of Evolutionary Biology arguing for a phylogenetic relationship between birds and dinosaurs (to which Todd Wood has subsequently responded). It certainly seems from this latest offering that Phil Senter is intending to keep creationists on their toes. And that, in my opinion, is no bad thing.
Senter P., Cole S. J. 2011. “Dinosaur” petroglyphs at Kachina Bridge site, Natural Bridges National Monument, southeastern Utah: not dinosaurs after all. Palaeontologia Electronica 14(1);2A:5p.