Ivory tower theorists have lots oftrouble with any idea that does not accept evolution and their self created ideas. Some folks have been working in the Picket Wire area and believe that petroglyphs there include proto-Hebrew alphabet images.
Scroll down to the article Colorado petroglyphs explained which is on the right of the page and click to read. The site has lots of ideas on the homepage to challenge new thinking.
Unrelated, some of my petroglyph photos from Lake County Oregon.