Brent, your guess is as good as (or better than) mine, but all the snake eggs I'm familiar with are soft, so turtle seems the safest bet. We had several pet desert tortoises in the yard when I was growing up, and their eggs were roughly the size and shape of ping pong balls, with fairly rigid shells--but they buried them completely. If you want to find out for sure, maybe you could rig a little fence of hardware cloth around them to trap the hatchlings long enough for a look. If you do, though, provide some shade so they don't hatch and get cooked by the sun.
Nice find, AnnieBee, and good job taking the time to ID it! Funny, Caneyscud--I've done my share of jumping out of my skin at things that appear too close when I least expect it.
Almost 30 years ago I was down in Mexico playing field assistant to a herpetologist collecting specimens for a university. One of our collection methods was to walk through the brush at night with Coleman lanterns, looking for rattlesnakes and any other nocturnal herps. The worst was when I'd disturb a sleeping wild burro, which would suddenly leap up with a deafening hee-haw (a totally inadequate description of that awful sound) and go crashing away through the bushes. The first time it happened I didn't have a clue what it was, and thought I was about to be killed.
Bill, that gator would have definitely caused me a case of the willies! I had to attend a zoo conference in Orlando quite a few years ago, and as I'd always wanted to go snake hunting in Florida, talked my previously-mentioned friend into meeting me there to see if we could find any critters after the conference. We had no idea where to go looking, though, so it certainly didn't live up to our boyhood imaginations. Mostly we kept running into what might have been some kind of banana spiders that built their webs at nose-height above the trail. They would cause some major gyrations when we'd run into a web and paste it's occupant right between our eyes. No snakes, though--although we did see a small 2-3 foot gator resting on a log out in a pond/swampy area at a little nature park. I hope you had better luck, despite your gator scare!