The dive plan for Day Six, the final day of our expedition, has some particular considerations. A good part of the team is returning to the U.S. the next morning, so in order to follow standard diving safety practices, we need to leave a 24-hour window between the dive and their flight. We decide to return to a cenote we first dove on in the previous expedition; it's nearby and relatively accessible, which will allow us to get in the water quickly. On our first dive, we found some significant artifacts and human remains at the site. It would be great to have another opportunity to explore this relatively large and very deep cenote.

We've nicknamed this site Crocodile. On our first expedition, as we were driving down a small asphalt lane on the way out to the cenote, a carload of state ecology officials approached from the opposite direction. Recognizing Memo's van, they stopped. Pleasantries were exchanged, followed by a couple minutes of rapid-fire Spanish, furious nodding, and then it was over and everyone was again on their way.

"So the ecology officials just came from the cenote," Memo announced. "They say there's a crocodile in it."

"Holy $%&, Memo. What did you say?"

Memo shrugged, "I asked them, how big is it?"

We never encountered the croc on that dive, and I always half-assumed the story was cooked up to a) ward off looters or b) entertain the gringos. But as we're driving back to the site on this sunny early morning, I discover that the ecology folks have been prodigously snapping photos of our cenote guardian. "Oh yeah, he's there. Absolutely," Memo assures me.

As we're running through our final gear check at the cenote's entrance, however, my concern is with the adult and child remains, and the thousand-year-old pottery we found here the last time. Crocodile is on community-owned property, on the edge of a village that keeps a close eye on its cenotes and close tabs on outsiders--but that's no guarantee that looters haven't paid the site a visit.

Fortunately, by the time we swim the 125 feet to the bottom of the debris pile, my fears are allayed. Nothing appears to be disturbed. On our swim back up, we observe more pottery and, at around 65 feet, a very strange find: on a far side of the cavern, wedged in a crevice between two enormous boulders, is a cache of deer antlers. There are at least 15, 20 of them, and each one shows marks where it was sawn off of a skull. How in the world did they get here?

Memo's co-star from the May/June cover is still in his original place. We were concerned that he may have been paid a visit by looters or less scrupulous photographers, who often pose and relocate human remains and artifacts for a more "traditional" shot.

(Melisa French)

We make it out of the water before our 24-hour window expires, and without encountering our elusive reptilian buddy.

In six days, we've had fires, poisonous snakes, and some pretty questionable descent/ascent methods. But at the end, we're all here and in relatively good shape. We also discovered two compelling sites that warrant serious archaeological investigation: Treehole II, and Cow Hole. In the coming weeks, Memo will prepare his report to INAH on the expedition and hope to squeeze in a few dives here and there between his teaching obligations and research. The rest of us have our jobs in the States to return to, but we all promise to meet up again in the fall for another week of cenote exploration. Next time, I'm demanding proof positive of that croc.