One thing that might help you to see what these markings are, is to do a "rubbing" of it........... take a piece of tracing paper and hold it tightly on the place where the markings are, and then take a number 2 pencil, sharpened, and rub it so that there is the most amount of lead possible on the point to contact the paper. try it a few times, and maybe you can see what is there. that has helped lots of people see the markings on stuff, including tomb stones. hope it helps ya!