Sometimes nature suggests human activity when there has been none.
Sometimes nature suggests human activity even where there has been none. As soon as I saw these natural patterns at the Valley of Fire State Park in Nevada on October 24th they reminded me of the petroglyphs you looked at last time.
Thanks to three commenters on that previous post, I now know that the darker markings on the stone shown here are likely to be desert varnish. The areas that tend toward black would have more manganese in them, and the reddish areas more iron. Live and learn.
© 2016 Steven Schwartzman