You should try to find Gloria Farley’s “THey All Discovered America. For 40 years she has tracked down and photographed writing and designs on rock walls throughout the US. Some may be as old as 4,000 years, and many are at least 2,000 years old. Aside from Vikings and runes, there is Celt-Iberian, north African, phonecian(sp?) and other scripts. I don’t recall seeing any Islamic Arabic writing shown. The north African and Iberian scripts mostly predated the rise of Islam.