Editor’s note: This is a companion to the essay "How Pollen Solved a 10,000 Year Old Mystery", which appeared in the May 2003 CAP Newsletter. Thank you so much, Vaughn, for sharing these fascinating and thought-provoking essays with us!! Mary Vetter

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It was a sultry June evening in 1971, with temperatures still hovering in the mid 80s when I entered the Houston airport and walked to the check-in counter. From there it was a long walk to the gate where a Braniff 707 would carry me to Miami, then south to Panama City, and finally on to Lima, Peru. Walking through the airport, I kept getting stares from other passengers dressed in tee shirts, shorts, and sneakers. After all, I was dressed in long pants, a long sleeve shirt, and had a down jacket slung over my shoulder. I guess they suspected I wasn’t headed for someplace else in Texas!

After a brief stopover in Miami the packed jet cruised down the runway and headed south for Panama. It was nearly midnight as we climbed above the clouds and the cabin lights dimmed. Some passengers tried to sleep while others tried to read.

It was raining when we landed in Panama and most passengers deplaned for the two-hour wait before we left for Lima. The enclosure where we were confined was spacious, but hot and humid. Lacking air conditioning, the windows were open but there was no cooling breeze as we listened to rain drops pelting the banana and palm leaves outside. Everyone smoked in those days so soon the room was filled with a haze of cigarette and cigar smoke, which added to the discomfort of some.

At 39,000 feet sunrise comes much sooner than on the ground. As we began our descent into Lima the plane’s wings reflected brilliant sunlight into the cabin where passengers were beginning to stir and took turns heading for the small closet-size bathrooms in the rear. After being awake all night I was groggy, but tried to freshen up with cold water and a cup of hot coffee. I had grown up in various cities in South America, including Lima, but I had left there when I was only four. It would be fun to return, I thought, but I also knew that I wouldn’t have time to see the sights before my next flight left for Ayacucho, high in the Andes.

I didn’t get to see much of Lima as the plane descended because of "La Garuùa," the name they give to the fog that drifts in from the cold ocean and rolls up the western side of the Andes in an engulfing blanket. It was cold, dark, and foggy when we landed at the Lima airport, known for its spartan facilities. That early Sunday morning there were no booths selling curios, food, or even magazines and newspapers. All I saw were rows of metal seats where weary travelers could stop and rest between flights. I made my way to the Lansa Airline booth and handed my ticket to a lone clerk. In Spanish she said my flight would leave on time in two hours from gate 7. I found one of the metal seats, sat down, and zipped up my down jacket. The airport windows were open and the fog crept in and settled on everything like a heavy dew. I watched as people passed by and left imprints of each step on the slippery, black-tiled floor.

Two hours later I walked across the tarmac and up a metal ramp to board an old, four-engine plane with faded markings. I hesitated for a few moments wondering if I should board what looked like a relic purchased as surplus after WW II. Inside there was no carpeted floors or insulation on the walls. Wires of all kinds ran in rows through holes in the rib frames above the windows while below the seats were bolted to rails on the aluminum floor with large wing nuts. In the back, rows of seats had been removed and replaced with large wooden boxes of fresh produce for the trip to Ayacucho. As the plane lumbered down the runway, the noise inside the cabin was deafening. I had a window seat but could see nothing but the outline of a wing in the dense fog. Minutes later we suddenly climbed above La Garuùa and into a cloudless, brilliant sky. Below me lay the jagged slopes of the Andes with their thin ribbons of green in the narrow valleys formed by streams and rivers flowing toward the sea.

As the plane climbed higher and higher I zipped up my down jacket, put on my hat and stared out the window looking for any signs of life on the barren slopes below. I was still looking out the window when the stewardess tapped me on the shoulder and handed me a piece of surgical tubing about 3/8" in diameter. I looked puzzled so the stewardess pointed to the front of the plane where two large oxygen bottles were strapped to the wall next to the door of the captain’s cabin. From there, a labyrinth of tubes, such as the one I was handed, flowed down the center aisle to each seat. I knew the plane wasn’t pressurized, so I suspected my labored breathing and the chill in the cabin meant we were climbing high over the Andes to reach Ayacucho. I put the tube in my mouth, inhaled the oxygen, and soon my head began to clear. I must have dozed off for a few minutes because when I awoke the plane was bucking from turbulence and the stewardess was yelling at some old Peruvian man across the aisle to put his seatbelt on. As I sucked on my tube, I looked out the window and watched the right wing move rapidly up and down as we hit each air pocket. I closed my eyes and said a prayer, "God, please don’t let the wing fall off this old crate!"

When I opened my eyes again, my window was suddenly smeared with droplets of oil flowing in a steady stream from both engines. I leaned forward and saw little rivulets of oil flowing from the sides of the engine cowlings and then down the top of the wing. I looked down and all I could see were the jagged, snow-covered peaks of the Andes.

I couldn’t leave my seat because of my oxygen supply, so I began waving frantically hoping to attract the stewardess’ attention. A few seconds later she was next to my seat wearing a portable breathing mask. I pulled out my breathing tube, pointed at the oil on the window, and yelled over the incessant roar of the engines, "Mira, aceite!" The stewardess smiled, took off her breathing mask, leaned over and said loudly in Spanish, "The engines have enough oil to make it to Ayacucho." She then turned and calmly walked back to her seat in the rear of the plane.

She was right, a little over an hour later we landed on the dirt and gravel runway in Ayacucho. I have no fear of flying, but for once I was glad to get off an airplane!

Ayacucho is located on a high plateau at about 9,000 feet elevation near the famous Pampa de la Quinua where Simon Bolivar's troops sealed the independence of an entire continent by defeating the Spanish army in the famous battle of Ayacucho on December 9, 1824. This town of nearly 60,000 had once served as the staging area for that battle, but today it was one of Peru’s largest cities even though it has only 10 km of paved and cobblestone streets. The rest were gravel and dust.

Richard (Scotty) MacNeish met me at the plane with his chain-smoking Peruvian driver who picked up my bags and headed for a nearby Land Rover. Ten minutes later we were in front of a two-story concrete-block house with a red tile roof and small interior courtyard. This was the headquarters for the MacNeish archaeological team. I was dead tired, but too excited to sleep so Scotty took me on a walking tour of downtown Ayacucho, located only a kilometer away.

The city center was an interesting place. There were rows of small shops along both sides of the narrow cobblestone street leading to the central plaza with its benches, greenery, and large Catholic church at one end. Old cars, diesel-belching buses, wooden push carts, and a steady stream of llamas loaded with all sorts of goods slowly inched along the street and around the plaza. Along the sidewalks and in the plaza were barefooted women wrapped in hand-woven blankets with black bowler hats on their heads and colorful slings around their necks cradling small babies that looked no larger than toy dolls. Scotty and I are not tall men, but we towered over the local Indians most of whom were barely five feet tall. Along one side of the plaza were women vendors sitting on flattened cardboard boxes selling potatoes, quinoa seeds, alpaca blankets and an array of other food items, cigarettes, live guinea pigs, and open burlap sacks of beans, dried corn, and wheat. As we walked along I noticed one woman doing a brisk business selling leaves that she would carefully wrap in pieces of old newspaper. With each sale she would hand the customer a small chuck of black material that she would break off from what looked like a large, black salt lick. I walked over to her and asked in Spanish what she was selling. She looked up with a stare that suggested she didn’t hear me, so I repeated my question, but still got no reply.

"She probably only knows Quechua," Scotty said between puffs on his cigarette. In the weeks to come I discovered that neither Spanish nor English was of any use once I ventured into the countryside. Most of the time I had to take a translator with me who could speak Quechua and Spanish.

I leaned over and picked up several of the leaves and began to examine them carefully. "My God!" I said to Scotty, "these are coca leaves and she has several twenty-pound bags of them!"

Scotty just laughed, "All the locals up here chew this stuff; it deadens hunger pains. See that black, rock-looking stuff? That’s a mixture of ash, lime, and salt. You have to chew it with the leaves to get any effect."

I bought a small handful of the leaves, got a small piece of the black rock and tried it. After a few minutes my mouth and lips got numb and I began to droll black liquid from the corners of my mouth. I spit it out and decided I would rather eat food to deaden hunger pains.

I don’t remember much more about that first day except that I fell asleep fully clothed and wrapped in a blanket on my cot sometime that afternoon.

The next morning someone knocked on my bedroom door. I looked out my small window and could see the first rays of sunrise peeking over the distant mountains. The rays made an arc in the sky that looked like the background in one of those framed, black-felt religious paintings of Jesus you can buy in Mexico. After a quick breakfast and several cups of strong Peruvian coffee, Scotty rounded up the rest of the crew and we were off to the cave site of Pikimachay, about 25 km north of town.

I had slept in my down jacket and I still had it on as I headed for the truck. As I labored to breathe at the high altitude small puffs of steam formed in front of my face in the chilly, winter air. I was in the lead pickup sitting in the front seat next to the chain-smoking Peruvian driver while six other Peruvian workers huddled in the truck’s bed next to screens, buckets, shovels, and ladders. Behind us in the Land Rover were Scotty and several visiting archeologists from England. Bringing up the rear was another pickup with the rest of the Peruvian workers.

There is only one, narrow, gravel road up the mountain from Lima to Ayacucho and we were on it inching our way down the mountain to the site. Lima is about 500 km east of the city, but it is a 12-hour, bumpy drive, provided there is little traffic. In most places the road narrows to a single lane and is barely wide enough for a bus or truck, but it does widen out every few hundred yards so that two-way traffic can past. The road is cut into the side of a steep mountain, has a bad washboard ripple on every curve, and no guard rail along the outside edge.

As we hurried down the road I peered out my window and looked almost straight down at a long talus slope that ended at a small stream several thousand feet below. There were no trees, only a jumbled mass of gravel and large boulders on the slope. "Jesús Cristo!" I yelled in Spanish as we neared each curve and the truck’s rear end bucked and skidded around the curve on the washboard surface!

"Slow down," I pleaded in Spanish to the driver who just kept puffing away on a hand-rolled cigarette. "What if someone is driving up the mountain, you will hit them because it’s too narrow for two cars to pass!"

He just smiled and without ever removing his cigarette, whispered, "No problem, it has never happened!" His reassurance was little comfort knowing that if it happened we would be lying in a wrecked pile at the bottom of that steep ravine looking like the many rusting and crumpled trucks and buses I saw in the rocky streambed as we whizzed around one curve after another on the way to the site. Driving to and from the site was like a parachute jump. I knew that all it takes is one mistake!

Pikimachay is a large solution cave, hollowed out of the limestone about 300 meters below the top of a mountain. I could see the cave clearly from the small side road where we parked. Below the cave were concentric rings of stone walls about a meter high. Behind each wall were flat, narrow bands of slope-washed soils where fields of corn, gourds, beans, potatoes and quinoa once grew.

We parked, unloaded, and began walking up a narrow trail to the site. Inside in front were the remains of massive roof falls with boulders weighing dozens of tons. Thirty feet above the boulders the soot-darkened ceiling arched in a graceful curve until it reached the back of the cave some sixty meters away. On one side near the middle of the cave and in back were several large, square pits where the team had begun excavations the previous summer and continued to dig. The largest pit, next to the roof fall, was about three meters wide and four meters deep. The straight walls had many rows of parallel scars where iron stakes had been driven into the hard layers to loosen the dirt for screening. These ended at the uneven surface of the cave’s bedrock floor. Soon, one of the workers arrived and slipped a ladder into the pit so that Scotty and I could climb down and stand on bedrock. I watched as he pointed to one feature after another and as his trowel followed along various unevenly-drawn lines that defined each zone.

"Before we began, it took us several weeks to blast and chisel away a giant boulder that covered this spot," Scotty said. "Next, we had to drive steel rods down a few inches at a time to pry loose the calcified soils. It was tough going and took us all summer, but it turned out to be our best pit because we could be certain that there was no mixing by rodent burrows."

I was spellbound at Scotty’s explanations and by the remains of sloth and horse bones still visible in the sides of one profile wall. "See this sloth rib," Scotty said with a smile, "it’s burned and pieces of it have been dated as being more than 15,000 years old. Even better, look lower in the profile; see those broken bones? They were found with chopper-type biface tools dating nearly 27,000 years old," he chuckled.

Dr. Liz Wing, from the University of Florida shook her head and reminded Scotty, "Don’t forget that we found some sheep feces mixed with some of the earliest corn cobs yet found at this site!"

"Ok, maybe some of the upper deposits were mixed by burrowing rodents, but those burned sloth and horse bones were below the massive rock fall and in the zone we had to chisel out with picks! No rodents burrowed in that layer," Scotty continued as he puffed on a cigarette.

"I’d sure like to see some of those Clovis First boys try to explain this site away," Scotty grinned. "Either people built a fire and ate barbequed sloth ribs down here before any Clovis folks even arrived in North America, or a slot was hit by lightning, ran into the cave while he was still on fire, sat down in a pile of firewood that somehow caught fire and then burned him to a crisp!" We all laughed at that remark and then continued on our tour of the site.

For the next few months I spent much of my time studying the regional vegetation from the high Puna at 15,000 feet where the ground was frozen a few inches below the surface, down to the nearby river valleys where narrow bands of vegetation clung tenaciously to the thin layers of soil. I also visited a host of other archaeological sites that Scotty had tested and which he believed would help unravel the mysteries of when and where the first peoples lived in South America and where they would later begin plant and animal domestication. Throughout that summer I collected a suitcase full of soil samples from excavation pits, from features, and from surfaces in and around the caves. I also collected bags full of suspected human coprolites (preserved feces) and took copious notes about the vegetation.

It was an exciting time in the early days of my career. I was a trained palynologist who was being given an opportunity to work at what researchers believed would become the key archaeological region in South America. Scotty MacNeish’s name was legendary after his recent discovery of agricultural origins in Mesoamerica at sites in the Tehuacan Valley of Mexico. However, using fossil pollen as an interpretive tool in archaeology was still in its infancy. Nevertheless, Scotty believed it might prove useful and thus had invited me to Peru as part of his archaeological team.

In late summer I packed my bags and four additional suitcases full of dirt and coprolites that I had diligently collected over the past months. As Scotty drove me to the airport, I knew that I was in for another hair-raising plane ride back to Lima. I was right! The four-engine prop, surplus-age airplane lumbered down the dirt runway trying to build up enough speed at that high elevation to get airborne. The runway ended at the edge of a sheer cliff and as the wheels barely left the ground the plane began a steep dive into the deep canyon below. I looked out my window just in time to see an overloaded bus and several trucks "above us" on the narrow road leading to Ayacucho. My heart raced as the plane continued its steep dive for several thousand feet until it finally had enough lift and speed to began its slow assent out of the canyon and over the Andes to Lima! The flight back to Lima, and then trying to get through US customs with four suitcases full of dirt and coprolites is another story worth telling some day, but not now!

During the next year our pollen lab buzzed with excitement as we carefully and painstakingly unwrapped and then processed each sample searching for fossil pollen. Sample after sample was a disappointment. Each dirt sample from one of the sites was void of fossil pollen. Where was the fossil pollen, we wondered? Maybe we were making errors in our processing techniques? However, the Peruvian surface samples were full of exotic pollen types so we knew the ancient samples must have contained pollen at one time. What had destroyed the fossil pollen? Carefully, we checked and rechecked our samples and procedures. Finally, when all the samples were finished we conceded defeat. Except for pollen in some of the human coprolites and from the surface samples, all the other archaeological samples were empty.

Gone was my hope for fame and immortality. I had hoped to be able to announce to the world the finding of the earliest plant cultigen pollen in the New World. I had hoped to be the first to report on the environmental changes in the Andean region of South America during the late Pleistocene and early Holocene. I had hoped to link my name and research to the many articles and later books that were being written about these famous Peruvian sites. But, I knew with no fossil pollen story to tell, I was going to be out of luck.

Ayacucho was to become the first of many later disappointments while searching for pollen at sites linked to the arrival and culture of the earliest Paleoamericans. After Ayacucho I examined numerous soil samples from the Marmes Site in Washington State. A decade later Scotty MacNeish gave me samples he had saved from Tehuacan, Tamaulipas, and other key sites in northern Mexico. During the 1980s, James Adovasio asked me to examine a long sequence of soil samples from profiles at the Meadowcroft Site. Throughout the 1980s I repeatedly sampled profiles of the Paleoamerican site at Lubbock Lake on the High Plains of Texas. I also collected and examined soil samples from the Paleoamerican site of Wilson-Leonard located near Austin, Texas. In the late 1990s I collected and examined a series of soil samples from Clovis and Pre-Clovis cultural levels at the Gault Site located east of Waco, Texas. Not one of those hundreds of soil samples contained enough fossil pollen to reconstruct any type of important information.

Because fossil pollen can be found by the millions in some deposits and can disappear completely in other soils, I have spent more than 30 years searching for the reasons why pollen remains preserved in some deposits and disintegrates in others. I have not worked alone in this quest. Others also have searched for answers. Today, our combined efforts give us a better idea of why fossil pollen is recoverable in some regions and from some soils of the world but not from others. Unfortunately, many of the Paleoamerican sites fall into the "other" group. Bonfire Shelter, which I reported on in an earlier CAP article, is one of the few exceptions where fossil pollen could be recovered and where it helped unlock some important mysteries.

We now know that most open sites, regardless of geographical location, are poor places to hope for fossil pollen recovery. This does not mean that the search for fossil pollen should be abandoned at "all" open sites. Instead, it means that most searches will end in disappointment. The soils in open sites are subjected to repeated cycles of wetting and drying, which we have discovered will quickly lead to the destruction of fossil pollen. The thin walls of pollen, whether fresh or fossil, are like a sponge that will expand or contract, depending on the available moisture. A sponge is soft and repeated wetting and drying cycles do not injure it. Pollen walls are more brittle and as they expand and contract, they react similar to a wire that is bent back and forth; at some point they break. Like an egg, a pollen grain is strong until it is cracked. Once cracked, pollen grains disintegrate into tiny, unrecognizable pieces. Experiments also reveal that a number of microbes (bacteria and fungi) feed on the cytoplasm inside fresh pollen. As they enter pollen grains they often damage or crack the walls of grains. Some tests reveal that even after pollen grains become fossilized some forms of bacteria will attack the walls in search of nutrients.

Soil pH and Eh also play key roles in determining when pollen will remain preserved or destroyed. Soil pH (ratio of positive H+ ions to negative OH- ions) can be negative, positive or neutral. As the pH, or positive factor increases, the soil becomes more alkaline and loss of fossil pollen also increases. When soil Eh (oxidation/reduction ratio based on oxygen diffusion) is high it reflects abundant oxygen. As aerobic condition increase, fossil pollen loss increases.

Finally, there are genetic factors that determine how large, strong, thick, and stable individual pollen grains will be. Some plants produce very fragile pollen grains that disintegrate quickly even under fairly favorable environmental conditions. Other plants produce very thick and strong pollen grains that often can be recovered even from some of the harshest soil environments.

For fossil pollen studies of any archaeological site, a thorough knowledge of the soil composition and chemistry, environment of deposition, possible climatic cycles during the past, and the potential for soil microbe growth are essential. Once these factors are known, a fairly accurate guess as to the potential for fossil recovery is often possible.

So where would be the best places to find the remains of Paleoamericans associated with well preserved fossil pollen records? Locations where the soils are powder dry and have not been exposed to cycles of wetting and drying would be ideal. Sites underwater in anaerobic locations would be excellent, especially if the water is near freezing. Sites that have been locked in ice for centuries often produce pristine samples of fossil pollen. Sites, such as Monte Verde in South America, and others in the Arctic where bogs have covered a site usually produce excellent fossil pollen records.

In over 30 years of searching for fossil pollen at Paleoamerican sites I have only been lucky once (Bonfire Shelter), yet I remain excited and optimistic. During the past several decades we have expanded our search for fossil pollen to include phytoliths (diagnostic silica plant crystals), which preserve under a different set of soil conditions than pollen. In this century we are adding the search for reserve starch grains (water-insoluble granules produced in copious numbers by some types of plants) and recovery of ancient DNA in our quest to unravel the mysteries of the past.

I firmly believe that the best is yet to come. More than 30 years ago when I began my graduate studies, one of the newest techniques was searching for fossil pollen. We still search for fossil pollen at Paleoamerican sites, but now we have a larger arsenal that includes phytoliths, starch grains, and DNA!

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This article first appeared in CAP Newsletter 26(2):10-15, 2003.