Submerged

by Daniel Lenihan

  The interior “frontier” checkpoints in those days had rectangular white signs that looked like those greeting the motorist entering a small town in the United States. The “alto” was in small black capital letters but meant “stop” nevertheless. Given the sociopolitical mood in Mexico at the time, it was wise to obey. Another series of apologetic explanations and we were on our way again. So much for collect-your-nerves snoozes; an auspicious beginning to what would prove to be an extremely event-filled eleven days.

  The air in this part of Mexico was wet and thick. As we moved deeper into the Huatla range, the pungent essence de Méxique seemed stronger. I was more accustomed to the western portion of the Mexican “frontier” where the air is dry and crisp, even as you approach the Sea of Cortez. Physical similarities to Sonora and Sinaloa are few, but the feel of Mexico is similar.

  There was a different ethic in Mexico regarding litter, which adorned the roadside with such consistency that a break in its presence startled the eye. A gap in the endless strip of roadside pampers, Agua Mineral cartons, cement bags, and broken glass would have seemed like a fault in an embroidered hemline. This fed the perception of Americanos del Norte that Mexico is “dirty.” At the turn of the millennium this ethic seems to be transforming.

  I’m old enough to recall the early fifties in the United States when the anti-litter campaign was just getting into full swing. The automobile window was God’s own trash disposal until we Americans of the North decided littering was unwholesome. Concepts of dirt and disorder are largely cultural phenomena. Cultural anthropologists have written much on this subject. Some iconoclasts of the environmentalist persuasion, such as Edward Abbey, have even suggested the real environmental wound is the road, not the litter. He made a point of always throwing his drink cans out of his car window in symbolic protest to paved roads.

  “Bonjour,” Paul greeted the man on the donkey-drawn cart. Cognizant his strong point wasn’t language skills, he then leaned back in his seat to let Sheck continue the conversation.

  “Señor, ¿dónde está el nacimiento del Río Sabinas? ¿Allá? ¿Es Allá?” Sheck was pointing through the mud-spattered windshield of the van as he finished his query about the birthplace of the Sabinas River.

  “Sí, allá” from the man who pointed over his left shoulder with his right hand while never letting his gaze wander from the front seat of our van.

  “Cuántos kilometros?” I piped in.

  “T oo many” he said in English, glancing down at our wheels, which were one-quarter buried in the mud. We had been following the dirt road for several miles after having noted clear water passing under the paved highway several miles back. In this area, clear water meant groundwater; groundwater meant springs; springs meant the possibility of underwater caves.

  “Gracias, buenos tardes, señor.”

  The man on the cart smiled, flicked the reins, and replied “De nada.” Glancing at Paul he waved and bid him “Bonjour” as he rolled on. We could roll nowhere ourselves until the other van and the four-wheel-drive vehicles showed up. All of us would push like crazy to get the vans going again and the remainder jump into their four-wheelers, as the procession pushed into the hills.

  An hour later we located the artesian spring from which flowed clear subterranean waters that downstream merged with ordinary surface runoff to form the Río Sabinas. We couldn’t care less about the river—it was the springs and the caves within, that is, the birthplaces of the rivers, that had drawn us so many miles.

  We persevered until we found our spring in a rugged area with some flat heavily vegetated land around it. After a night’s sleep in a meadow next to Río Sabinas, we were ready to begin our exploration.

  The several-hundred-yard walk and stumble over river cobbles with full cave-diving gear were hard on my wet-suit-clad feet. The oversized double cylinders on my back weighed more than a hundred pounds, particularly since they had been stuffed with air well beyond any legal or prudent limit. The tanks were each capable of holding 102 cubic feet of compressed air when filled to their normal working pressure of 2,400 Pounds per Square Inch (PSI). These babies were supercharged to 3,400 PSI, their overpressure ports neutralized by our inserting two bursting disks where only one was indicated. Of course, this meant the tank would explode before the safety disks ruptured and harmlessly released the air. But we had weighed that possibility against the consequence of running out of air in a cave and made a choice.

  The propriety of such treatment of diving cylinders is more than a little arguable, but to a team of divers about to push the envelope in cave exploration, the niceties of cylinder handling is far outweighed by a desire to carry a lot of air. With the steel pressing heavily on my back, the array of lighting systems pulling down heavily at my waist, and each step a challenge in balance, I began uttering silent prayers that I would make it to the spring where I could at least drown in comfort. Once there, it took a while to compose ourselves for the dive. A couple of our team members had managed to drag small oxygen cylinders along to aid in the decompression.

  After recovering from the exertion of getting to the water, we slipped below the surface and were greeted by the familiar relief of the weight lifting from shoulder straps and waist. The myriad lights and gauges and hoses that encumber a fully equipped cavediver seemed to rearrange with a mind of their own into a much more logical configuration. Dive gear, particularly cave-diving gear, is meant for swimming, not for ambulatory humans.

  A spelunker named Bill Stone had reported that there was a serious cave here, and from the size of entrance and the force of the outflow we had little doubt he was correct. Bill would, in later years, become a well-known cave diver in his own right, but, at this point, he was passing on his subaqueous finds to Sheck. There were five of us on this dive: an unusual number. We preferred diving in twos and threes and occasionally fours. Everyone was hoping to get a shot at Sabinas before the thunderheads moved in. It had been hard enough driving into this place and we didn’t want to push our luck.

  At 180 feet deep the angle of repose of the bottom cobbles became even steeper, and the ceiling came down sharply to meet it. The cobbles had the disconcerting tendency to slide and roll if we touched them with our fins. This happened more often as we were forced closer to them by the converging ceiling. Presently we were faced with a major constriction. Where the ceiling met the floor of the spring, the water was emerging from a very wide aperture not high enough to enter.

  We spent a couple minutes digging through the cobbles dog-style until we could make it through this tight point and were rewarded by the cave immediately opening up into a large tunnel with a more gentle slope. Jamie Stone, Carol Velice, and I kept to the ceiling while Sheck and Paul moved along the bottom twenty feet below us. We were now well over two hundred feet in depth and, after our digging exertion, were feeling no small amount of nitrogen narcosis.

  The trick with narcosis is to know when you’ve had enough on any given day. For whatever reasons, about five hundred feet into the penetration I started to react adversely to the depth: I felt slightly nauseated and increasingly apprehensive as the nitrogen “high” started turning into a low. I checked my depth gauge, which was reading 250 feet, and signaled to my partners by waving my light beam ahead of them in a swift, erratic motion. All stop!

  Had there been no further complications, I would have simply signaled my distress and indicated that I needed to “call” the dive. One of my nearest buddies would have accompanied me out while the others proceeded. I never had the chance to communicate further.

  As the team members turned to check on why I had flashed them, two events occurred almost simultaneously. Sheck’s sealed beam light imploded from the pressure with an ear-ringing “pow,” and we could hear a rumble from the direction of the entrance.

  It has always amazed me how things can go to hell so fast on a cave dive. One moment gliding through a new world, all receptors open to the excitement of the exploration, and the next, the distinctive fee
l of one’s mortality rising in one’s throat. My heart rate picked up perceptibly, and I took pains to calm my breathing before making a slow-motion turn and proceeding slowly back towards the entrance. Exertion, excitement—anything that could result in overbreathing the regulator—could be fatal in our present position.

  Air at this depth is very dense and harder to move through one’s internal airways and mechanical appendages. Increased exertion generates carbon dioxide, which, in turn, aggravates the narcotic effects of nitrogen, and an unpleasant series of effects quickly takes over which usually result in one becoming a statistic. Sheck and Paul, who had been moving below us on the floor of the tunnel, tied off the guideline before joining us on the ceiling for the trip out. Their tie off was 290 feet deep.

  Somehow, I wasn’t surprised at what awaited us at the constriction. A cloud of silt hung ominously in the otherwise crystal-clear water; it surrounded the point we had burrowed through, our white line pointing precisely back into the heart of the murky puff of smoky-looking silt. I ran my hand along the line and felt it disappear into a pile of those damn river cobbles. Since I hadn’t been in the best of shape before all this happened I decided to back out of the constriction and give my partners a shot at solving the puzzle. I settled back into the clear water and considered our situation.

  I recall how strangely calm I felt as I coldly started assessing our chances. They were really rather marginal. Within minutes, which seemed several hours, Paul came out of the cloud and motioned me back to the line. I followed him back into the silt and through an exit he had dug several yards over from our entry point. I shot him an okay signal (kissing him would have been awkward) and proceeded back to the decompression stops in a business-like fashion, striving to preserve the false impression that none of this had shaken me up.

  At the proper opportunity during the two hours we spent decompressing from the dive in the open part of the sink-hole, I swam discreetly over to the side of the spring. There, I vomited violently through my regulator. You can fool others, but it’s harder to fool yourself. I knew exactly how close that reaper had come.

  This was to become an extraordinarily thrill-packed week and a half. Each day brought a new cave and new discoveries. With the exception of the unpleasantness at the border we found the Mexican people very friendly and gracious to what must have been a bizarre-looking group. We would park our vehicles in fields or river washes on the edge of towns and bed down for the night, only to find in the morning that we were usually in some thoroughfare. People, pigs, donkeys, and chickens would be parading between us in the morning, going about their business. They were more tolerant of the crazy gringos than I’m sure we would have been of them if the situations were reversed.

  We found ourselves working in a karst system that was characterized by typically greater depth and greater temperature variation than the Florida caves. Some water was in the mid-60s Fahrenheit and in others it reached the low 80s. There were troglobitic creatures in some and amazing concentrations of prehistoric artifacts in others. The latter ranged from ceremonially “killed” ceramic vessels with telltale holes poked in the bottom, to ceramic figurines and alabaster “thunderbolts” cast by Aztec gods.

  One of the springs called Mante was an extraordinary place, a geologic fault that seemed to drop forever. With hardly any lateral penetration we reached depths over 270 feet. Sheck and Paul tied a line off here at 330 feet deep, deeper than one is ever supposed to go on air. Over the next ten years, Sheck would return to this spot in a Mexican cow pasture and set the world’s depth record for scuba diving and break it three times using a combination of helium and oxygen instead of air. He would eventually reach 860 feet deep and report a bottom still slanting down into some nameless underworld.

  The future was not on our minds, however; we were too absorbed with the discoveries and obstacles each day brought. A major problem was a lack of a compressor with sufficient delivery to keep up with so many tanks. We finally decided we had to make a run to Tampico, several hours away, to fill our tanks. There were no dive shops there at the time, but there was a Coca-Cola plant that needed compressed gas services. The “planta,” or drop place, for oxygen, carbon dioxide, and acetylene bottles in Tampico was called INFRA. The plant manager said it also had banks of compressed air to which he kindly provided us access. We prayed there was no breakdown in communication; a set of tanks mistakenly filled with oxygen would prove lethal at the depths we were diving.

  The air we obtained at INFRA was indeed air, but it had a funny taste, and if we were anyplace but this wonderland of opportunities we wouldn’t have dived with it. The biggest concern with contaminants in breathing air is the presence of carbon monoxide. It bonds with the hemoglobin in red blood cells much more readily than oxygen and can create a situation in which the diver can’t utilize the oxygen in the air being breathed. This happens even though there are more oxygen molecules actually available in the lungs because of the increased partial pressures at depth. The real irony is that if the diver gets deep enough, fast enough, the free molecules in the aqueous portions of the blood are so numerous that it can sustain the body’s needs until the return to shallow water where blackout occurs.

  Carbon monoxide is odorless and colorless but the by-products of combustion often give it away. It smells kind of like you were hanging around a bus station. This air didn’t have that odor, it just smelled . . . weird. We headed back inland with full tanks and heightened spirits—we were ready for anything.

  We arrived in Rio Verde, a small town on the way to San Luis Potosí. There were a series of springs there called Media Luna. We dived in the evening under a full moon in “half moon” spring. Unlike the other places we had been diving that were previously unexplored or “virgin” holes in cave diving’s hopelessly phallic prose, this place had been heavily dived. Mexicans and Americans from Texas had frequently used this attractive and easily accessible open series of open sinks for sport dives. At the hundred-foot-deep bottom, there was a “boil,” which is how cave divers refer to a strong outflow of water from a fissure in limestone. A tree trunk had fallen into the spring and was lodged into the crevice from which water was emerging with great force. The tree’s branches were vibrating in the strong current.

  We studied the situation for a few moments, and Sheck, Paul, and I tugged on the log until it pulled loose. Paul shined his light down to illuminate the fissure while Sheck and I pulled ourselves face first against the current through the restriction. It widened at about 130 feet deep, and the force of the water relented, allowing us to use our hands for things other than propulsion, such as switching on our primary lights.

  Sheck immediately started scanning the craggy interior of the room for further leads to increase our penetration. Meanwhile I picked up a shiny object reflecting in my light and studied with disbelief a perfectly formed alabaster serpent (variously interpreted as a thunderbolt). Almost everywhere I looked there were ceramic Aztec figurines, bones, and other artifacts. Returning from his probing of the chamber for more cave openings, Sheck stared wide-eyed at what I held in my hand. After several minutes staring at the treasures we returned them to the ledges where we had found them. Sheck took no convincing to do this; he respected the sanctity of caves. He has probably explored more underwater caves than anyone in the world but believed in leaving them the way he found them, natural and cultural wonders intact.

  Paul couldn’t tell from his vantage point at the top of the fissure what we were doing, but knew we were using precious air in a hole that obviously didn’t go anywhere. He waved his light several times to remind us what we were here for, and we reluctantly made our way out. I can’t account with confidence for the presence of those artifacts except to infer that they were ceremoniously tossed in the spring. Such a concentration of undamaged ornamental items in a small area suggests purposeful deposition for sacrificial purposes. The submerged spring would have appeared a mysterious dark blue spot during daylight hours—an inviting target. Also,
there is an ethnographic and archeological analogy for this occurring other places in Mexico, even in other springs we located on this trip. Why no one had ever pushed into the fissure before us is beyond me. I would keep its existence secret even now except for the knowledge that this hole has since been excavated by the Mexican Institute for Anthropology and History. One of our group removed and photographed one of the serpents before returning it. A copy of the photo in hand, I reported the find to Pilar Luna, the head of the group’s underwater program in 1980, and they took action by 1981.

  A particularly strange series of events took place when we visited the Hotel Tanunil, a rather fancy establishment oddly situated on the road from Vittoria to Tampico. We had literally drawn straws to determine which teams had the honor of being first to “penetrate a virgin system.” Although Sheck, Paul, and I had the first shot at Rio Verde, for some reason I can’t remember, I was still owed one when we pulled up to the office of the hotel.

  We weren’t interested in rooms since we were all camping, but the fellow at the desk had some intelligence about entry into Río Choy, a magnificent spring that you could drive to if you had a key to the gate. It was on property owned by the distinguished gentleman who was also proprietor of the hotel, one Señor Gaston Santos. For a reasonable consideration, we hoped the gate key might be obtainable from the desk clerk at the hotel.

  Meanwhile another contingent of our group had made the discovery that the swimming pool of the hotel was spring-fed, and even more compelling, the shed that comprised the well-house had a pipe disappearing into what appeared to be a limestone fault. While the dickering went on at the desk over the gate key, I quickly donned a single tank and grabbed a small secondary light, while Paul maneuvered the van to block any view of the well-house door from the hotel.