Well I do not think it is a sign for treasure; but if you google petrified Bigfoot skull, contact that fella and tell him you found another one at the bottom of that rock.
Since you posted this in the New Member Introductions SubForum - allow me to Welcome You Aboard Mina! You didn't list your state (or country) in your profile. So, you might consider jumping over to Sub-Forums: Select Your Area.... and selecting your state for information (i.e., clubs, hunts, finds, legends, maps, etc.) directly related to your state (or country).
Welcome from My wife and myself . As we are short timers here I can say this is a great site and the people here are very helpful and informative . I have researched sites like this for years and found this to be the best of them all. Looking at your picture it has a oddity i must admit but thats not my area of expertise but I am sure there are people here that can and will help you out a bit . In some instances you may want to keep an eye on the messages box at the top of your screen as i found many of the members contact you through that section when its in your better interest not to publicly post some information so you may want to keep an eye on that area. Once again welcome and I am sure your going to enjoy the site.
Excal 1000, Excal II, Sovereign GT, CZ-20, Tiger Shark, Tejon, GTI 1500, Surfmaster Pulse, CZ6a, DFX, AT PRO, Fisher 1235, Surf PI Pro, 1280-X, many more because I enjoy learning them. New Garrett Ca