Memo's base of operations is a small one-room building on a restored sisal plantation some 40 minutes south of Merída. By the time we get there in the morning, Memo's right-hand man Dioniso has already refilled the tanks we went through the day before. He also has a suggestion for how to start off the day: a cenote on a friend's property that noone's ever dived on. Even better, it's already got a fancy built-in ladder for its use as a swimming hole. We check our gear, which has been drying out overnight in the compressor room, for the ever-present spiders and scorpions, load the tanks into the van, and head out to request permission to dive the site.

Permission granted, we drive out a good ways into a scrubby orange plantation before finally arriving at the cenote. It's mid-morning and the heat is already shimmering off the parched grass. The one spot of shade is raging with Africanized ("killer") bees, and Pedro sets to them with his smoker. Sedated, they return to their hives and gorge on honey rather than attack. Memo decides to make a quick recon of the cenote before anyone else bothers to gear up and make an affair of lugging equipment down the posh 20-foot ladder. He's back up with his tank too soon: "I got down to about 15 feet, and it looked like there was a bit of a cave on one end, and then I just hit solid rock," he shrugs. The site gets dubbed "Cenote No." We pile back into the van, determined to fit in a second dive before sundown. Dionisio knows of another possible cenote on a nearby cattle ranch, and we drive into a small Maya village hoping to find the man who has the key to ranch gates. Again, we're in luck.

Cenote No: a pretty swimming hole, but nothing more (Kristin Romey)

Dirt paths outnumber paved roads in the Maya lowlands south of Merída, and it's a wonder that a passenger van overburdened with people and dive tanks can make the hour drive over the rocks and through the mesquite scrub to our second dive site of the day. Several huge mounds around the site suggest that we're in the middle of a large unexcavated settlement--things are looking promising again.

The entry to the cenote looks fairly steep and tricky, but doable with a rope. Most of the basin is covered with a large overhang, so it's difficult to gauge its size. As the equipment rigging is being set up, Geoff spots an interesting carving on the western lip of the cenote. All of a sudden, a familiar buzz erupts out of the basin. "The smoker! Light the $%# smoker!" This time, the bees are joined by angry wasps, and they alight on anything wearing a wetsuit. Dionisio tugs at his white T-shirt. "They like black," he grins. The dive team makes a quick rope-assisted descent into the cenote and a final slippery leap into the bat-guano-slicked water.

Geoff points out a carving on the cenote's lip (Alisa French)

One by one, the equipment rigs are lowered into the basin. The trick is to unhook your tank without getting stung by the dozens of thirsty insects crawling on the rope.

The air in the low cavern is close, fetid, and there's not much room to share with the bats. The situation below the surface doesn't improve much. We're in a silt pit. One wrong kick sends up a fine cloud of goo that takes minutes to settle back down. Toward the rear of the cenote, about 150 feet back and 60 feet down, there are the decomposed skeletal remains of one person. Nearby, there's a large pot. Ceramic sherds are poking through the silt everywhere. But the most obvious remains are the cattle bones--cows, cows, everywhere. Absolutely expected when you're diving in the middle of a cattle ranch.

Cows, cows, everywhere! (Melisa French)

When you're working on a non-recovery, non-disturbance survey, silt can be your worst enemy. The large mounds on the surface, and the human remains and the number of pottery sherds within the cenote all hint that there's much more going on there. The only thing that makes it easy not to start fanning away like a land archaeologist with a camel-hair brush is the knowledge that doing so may quickly zero out visibility across a good part of the site.

So Cenote No is a bust, but the Cow Pit can be considered a success in that we discovered archaeological material--just not a lot of it. And diving on a cattle ranch does have its perks, which we discover when the bees and wasps come at us with renewed vigor after the dive:

Flaming cow pies make great insect repellent!