From my knowledge about Petroglyphs which is somewhat extensive, many of them (as in this case) have "SHADOWS" connected to them, which means that you need to plant yourself there in the morning or evening for a extended period of time and take pic's for your record. Most of the time, it's involved with equinoxes and there is 4 of them, Spring, Summer, Fall, Winter, normally on the 21st of March, June, Sept. December. The "SUN" on the right is "WALKING", meaning that it's throwing a Shadow, I believe the other 2 posters here are correct about the 'other sun' which is most probably a TURTLE. The Spanish also imitated the Pecked Designs as well, so as not to Alert anyone. I have found this to be Very True. You can read about me and the Petroglyphs and Shadows under the Treasure Legends Thread, follow it to Aztec Gold, then scroll down to "THE RETURN OF THE GIANT SERPENT". I have many posts throughout Treasurenet, most of which is about the Spanish and Petroglyphs. But getting back to your interest here, there is more to this Petroglyph than what your showing in the pic, which you may not even realized it. Circles and Squares divided up into 4 or quarters are found throughout the world, make no mistake and they are as old as ancient man himself, but they DO MEAN DIFFERENT THINGS "WHEN ATTACHED" to other Petroglyphs. I know your asking a simple question but it's not simple cause your not showing or seeing everything. Why would anyone inscribe in any form on rocks that are uneven or close to faults, cracks, or even sometimes all the way around the rock? The answer is Greater than you think and it's by no mistake. So, it looks like you have a Project if you want to really find out what it means positively. Turtles, you know anything about Spanish Turtles, I think Alan Keyes wrote a Book about them...Try Amazon Books......Darrell