The Sediments of Time

by Meave Leakey

  The days passed happily. I didn’t have much time off, but whenever I did, friends showed me new and beautiful parts of Kenya. Before I knew it, it was time to return to Bangor to write up my thesis. My parents came out for a holiday before I was due to leave. I was shocked at how much my mother had aged—she clearly was not well—and I urged her to stay with me longer to recuperate. But at the end of a fantastic holiday together taking in many spectacular places in Kenya, my mother insisted on getting on the plane. She did not make it back to England alive.

  The anchor of our extremely close family was gone, and we were all devastated. I returned to a sombre homecoming, and the chore of writing up my thesis was clouded and rendered more onerous by my terrible grief.

  * * *

  BACK AT BANGOR, I buried myself in my work, attempting to come up with a family tree of the monkeys based on the differences in skeletal morphology. I was using a technique that was very new at the time—crunching numbers using multivariate analysis on a huge computer that nearly filled a whole room and running miles and miles of ticker tape with holes punched in it. This entailed very precise programming, and the computer frequently refused to run because I merely had a comma or a full stop erroneously placed. Today, my results would no doubt look archaic and not pass muster, but in those days, it was cutting-edge research.

  As I was finishing my thesis writing, word came that Cynthia had decided to give up her post at the Tigoni Primate Research Centre, leave Kenya, and travel overland to Zimbabwe with all her possessions and pets. In early 1969, PhD in hand, I returned to Kenya at Louis’s behest to take over the running of the centre. I had agreed to lend Louis a hand, but this was not how I wished to spend the rest of my career. I insisted that my role there would be limited to a six-month stint while I figured out my future plans.

  Not long after my arrival back at Tigoni, I received an urgent summons to Louis’s son’s office. Richard Leakey was running Louis’s affairs for him while he was away in the United States, and he had discovered the terrible state of finances in most of his father’s projects. It hadn’t taken him long to figure out that the monkeys were being fed like kings, and Richard called me in to tell me that my funds were going to be severely curtailed.

  Sitting behind a large tidy desk in a small bare office, he greeted me and went straight to the point. “I am sorry, but the funds for Tigoni are severely limited, and we have to find a way to spend less on the large number of caged monkeys,” he began. “How do you suggest that we might do this?”

  Richard was a man with a terrible reputation—irritable, impossible, irascible, and extremely arrogant are some of the epithets I’d heard with great regularity. I had approached this meeting with some trepidation and was curious to know if he deserved these awful labels. After I entered Richard’s office, however, it didn’t take me long to form a vastly different impression of the man. He was charismatic and charming, and we instantly liked each other.

  Instead of berating me for spending too much money, he suggested ways in which I could cut costs, and we discussed the general running of the centre and how things could be made more efficient and productive. It was hard for me to imagine that this was the same man some people called impossible.

  I began to see Richard quite regularly because he was publishing a paper on two important fossils—a colobine skeleton and a very early baboon skull—that he had discovered in fossil sites at Lake Baringo while leading an expedition there in 1966. Richard knew little about monkey anatomy, but by now, this was a forte of mine. I just happened to be dissecting a monkey at the time, and I invited Richard to help. Over the gory and malodourous insides of a large male colobus monkey, we shared the excitement of tracing the various muscles to their point of attachment on the long bones, and we followed nerves and blood vessels through the various fossae that enabled their passage.

  “Look at this tiny thumb, Richard, it is nothing like the thumb of the baboon that I was dissecting the other day,” I remarked.

  “Yes, all modern African colobines have small thumbs,” Richard observed. “They don’t need long thumbs to grab the leaves they eat, but baboons and guenons need a very precise grip to pick up the tiny seeds and fruits that they relish.”

  “True, and I am sure that thumbs really get in the way when you are swinging around in the trees the way the colobus monkeys do!” I laughed.

  This collaboration soon led to another, and Richard invited me to join his expedition on the eastern shores of Lake Rudolf (now Turkana) to study the fossil monkeys he was finding there. Naturally, I thought this was a grand idea.

  * * *

  IN JULY 1969, Richard drove me to Koobi Fora, a spectacular sandy spit extending into the lake where he had based his camp. We drove nonstop for hours in a bouncy old Ford Bronco with a fully laden trailer, leaving Nairobi sometime before dawn and arriving at one in the morning the following day. It was too dark to see very much, but I could just make out a line of tents along the shore. Richard showed me a small tent near the end of the line next to his larger one, and I gratefully jumped into the metal-frame bed inside, made up for me with sheets and a blanket. Before dropping off to a very deep and relaxed sleep, I briefly lay awake listening to the sound of lapping water on the lakeshore just outside my tent.

  I woke early, excited to see my surroundings and curious about the strange barks I had heard in the night. There was a large herd of zebra near my tent, which explained the unusual noises, and there were other herds of tiang and zebra grazing peacefully along the lakeshore in the early morning light. The camp was spread along the leeward beach, the small waves almost reaching the entrance to each tent. The horizon stretched for miles in all directions. The lake was a beautiful green-blue colour, which led to its informal name of the Jade Sea, and the hills on the far shore were just visible. I took a deep breath—it was magical.

  I made my way to the large mess tent for some tea, and I found it abuzz with excitement. The previous day, Kay Behrensmeyer, a Harvard University geology student who had joined the field expedition that year, had discovered some stone flakes eroding from a tuffaceous (volcanic ash) horizon about a two-hour drive from Koobi Fora. Based on the features of the fossils in the same layers, she believed these to be some of the earliest stone tools yet known. In spite of our late arrival the previous night, we immediately jumped back in the Bronco to check out Kay’s discovery.

  We drove with Kay and some of the field crew to a spot within walking distance of her site. Although we had driven this same road the night before, it had not been possible to see anything in the dark. Now I found the sandy ground covered by small bushes and shrubs, almost all armed with prickles. Acacia trees occasionally graced the landscape with their elegant slender trunks and tiny leaves. I was amazed by the abundance of wildlife—oryx, gazelle, Grévy’s zebra, Burchell’s zebra, ostrich, giraffe, dik-dik, hares, and exquisite gerenuks with delicate long necks and long limbs.

  After parking the car, Richard led us at a fast pace to the site. I wished we could go more slowly; I wanted to stop and look at the many intriguing rocks everywhere and check out those that I thought might be fossils. I was enthralled by my surroundings. Here, in contrast to the steep slopes of Olduvai Gorge, relatively flat badlands of sedimentary and fossiliferous exposures stretched in all directions.

  After about half an hour, we came to a small hill with a visible white tuffaceous bed halfway up.

  “Look at these,” Kay announced pointing to some smallish grey flakes lying on the surface of this tuff and on the slope just below it. “Surely these are tools. They are clearly flaked, and there are no rocks of this type in these sediments. They must have been carried here from elsewhere.”

  “Yes, indeed,” Richard said, smiling broadly. “These surely are stone tools. Congratulations, Kay! A wonderful, wonderful find!”

  This tuff later came to be called the KBS tuff after Kay Behrensmeyer, and the tool site was named the KBS site. Having seen what Kay had found, Richard immediate
ly realised that the previous year he too had seen similar flakes eroding out of this same tuffaceous horizon not far away.

  “Just wait here, I have to go to check something,” he remarked, before disappearing into the surrounding hills, mounds, and gullies made of exposed ancient sediments, which we call “exposures.” After walking for about half an hour, he found the spot from memory. Just as he had remembered, there were similar tools eroding out of the same tuffaceous bed. It was another tool site of the same age.

  Later that month, the field crew began a small excavation at Kay’s site to try to locate flakes in situ, as this would prove that the tools actually did derive from the tuff itself. This test-trench excavation was successful, and after about ten days, several flakes had been recovered in the tuffaceous horizon. This was a tremendous bonus for the expedition. The ability to make and use stone tools is one of the major milestones in our path to becoming human. Not only would this momentous discovery help our research, but this was the sort of find that would surely help persuade the National Geographic Society to extend their support of our fieldwork in future years.

  My own first intoxicating taste of discovery came the day after we had been sitting around the cooking fire arguing with Nzube about Neil Armstrong. Little did we know that our own exploration would take its own giant leap forward. After a simple supper of rice, baked beans, and corned beef cooked on a small fire, we had spent the night on tarpaulins under the most magnificent carpet of stars I had ever seen. We woke early, and after a quick cup of tea, we split up, with Kamoya and Nzube taking one area of exposures and Richard and I searching another.

  “If you find anything good, don’t pick it up but come and find us,” Richard called to them as they left. “And we will do the same.”

  Our plan was to find out how many fossils there were in this area and if it would be worth returning to spend more time here with a larger team. So we began searching the sediments carefully, peering at the ground and checking each and every fossil to be sure there were no hominins or other rare species. To my untrained eye, the ground seemed to be covered by a mass of rocks, pebbles, and stones of assorted shapes, colours, and sizes. I was quite put out and nonplussed when Richard immediately bent over and exclaimed, “Look, lots of fossils!” There was clearly more to this than I had anticipated. “Try focusing your search on the sides of erosion gullies where new bones are being exposed each time it rains,” he advised. But I still had little success. He, on the other hand, gleefully picked up and identified fragment after fragment of bone. “What am I doing wrong?” I finally asked with a note of desperation and frustration in my voice. “Well, it should be easy for you since you have spent so long looking at all those monkey bones you like dissecting so much!” he said unsympathetically. “What do you mean?” I retorted, starting to feel irritated with both of us. Eventually, Richard was able to explain to me that I needed a search image in my mind of the shape and size of the various parts of bones of different animal species. Without this mental template, it is impossible to pick out a partial bone from the mass of pebbles and stones that it is hidden in. The larger your reference library of search images, the better you are at finding fossils. Armed with this valuable insight, I was soon exclaiming excitedly over my own discoveries and entering into a spirit of competition about it all.

  It was a typical scorching morning, with not much wind. We had gone by camel to explore some exposures far away from camp. By eleven a.m., the temperature had easily climbed to around thirty-five degrees Celsius (the high nineties in Fahrenheit). Richard’s back was feeling the effects of a long camel ride, and I was thirsty and more than ready for a break. So we began heading back to the camels and were wandering down the sandy bed of a small dry stream when we came upon a sturdy, rounded object lying on the ground ahead of us. Staring at us from the sand was a perfect skull. We sat down and stared back.

  “Austr . . . Austr . . . Austr,” Richard gasped, looking very much as though he had seen a ghost. This was one of the only times in our entire life together that I have heard Richard fail to complete a word or a sentence coherently. The last rain must have eroded the stream bank enough to free the skull, and it had rolled into the riverbed. One more heavy downpour, and it would have been washed down the river and lost forever. It was one of those unforgettable moments when time stands still and you think you must be dreaming. Concerned that we might fail to find this site again, we erected a pile of stones on top of each of the low hills in the proximity of the sandy streambed before going off in search of our companions. When Kamoya and Nzube saw this spectacular fossil skull, they were as delighted and astounded as we were. They grabbed Richard, picked him up, and carried him on their shoulders shouting excitedly. Never again have I experienced quite such a thrilling and perfect discovery.

  Our camel trip was over barely before it had begun. We simply could not risk taking such a valuable find onwards with us on our expedition, for we were heading into country where dangerous, heavily armed shifta bandits rustle cattle. Instead, we turned around and rode triumphantly back to our base camp at Koobi Fora. Richard shared his mount with what was probably the earliest hominin to ever ride a camel.

  This skull was the 406th specimen from East Rudolf that we catalogued in the Nairobi National Museum collections, so it is, quite unimaginatively, called KNM-ER 406. It was the second-known complete skull of its species, Paranthropus boisei, and it was found almost exactly ten years to the day after Richard’s mother, Mary, found the first one at Olduvai George—the skull nicknamed Dear Boy and otherwise known as Zinjanthropus. We would have to find many more fossils over a span of decades before we could begin to properly comprehend how these two iconic specimens fit into the bigger picture of evolution.

  At Koobi Fora, I soon fell into the camp routine. The days went by rhythmically, each morning bringing a sense of purpose and anticipation. Would we find something important? What would we learn? Every day brought exciting discoveries, logistical obstacles, broken vehicles, or general mishaps. We would wake early, usually at five thirty a.m., just as the sky to the east began to lighten; emerge from our tents for a quick wash; and sometimes take a dip in the lake. After a quick cup of tea, we were off to the exposures to search for fossils just before the sun crept over the horizon and the scorching heat began.

  Although the idea of prospecting from camels sounds wildly romantic and exciting, the reality, apart from our astounding and miraculous discovery of 406, had proved rather more challenging and impractical. The camels were the most stubborn and wayward creatures I had ever encountered, and they walked so slowly that the entire endeavor was hugely time-consuming. Riding them is uncomfortable to put it mildly, so we usually preferred to walk beside them. At night, due to the large lion population, the camels had to be hobbled in a tight circle. We formed a surrounding protective ring around the camels, feeding a campfire through the night as a lion deterrent. Glad to have experienced a once-in-a-lifetime camel safari, I was relieved when we quietly returned to a motor-propelled conveyance for future forays into the exposures. This vehicle was a grey, battered, stripped-down Land Rover with no roof that we called Kilaloma. It could defy the most formidable rocks and slopes under the expert driving of both Kamoya and Richard, and it didn’t need night protection from lions or cajoling to go in a particular direction or at a particular speed.

  The drive out to the sites always gave us some unexpected pleasure as we would invariably see spectacular wildlife—herds of oryx; the spiral-horned, very shy kudu; and skittish gerenuk. If we were lucky, we would see some of the large carnivores, most often hyaena and lion but occasionally wild dog, leopard, or cheetah. We carried very little with us in the field—just a small bag containing a dental pick, some Bedacryl (fossil preservative), thinner, glue, and a paintbrush. Richard taught me how to use these staple items in a palaeontologist’s kit. Many fossils are not lying fully exposed or ready to pick up, and they are rather fragile. We would meticulously pick away at the ground they were
embedded in with retired dental picks that had been kindly donated by Nairobi dentists. After gently brushing away the loosened soil, we would paint the Bedacryl onto the exposed part of the fossil until it could be removed and carefully packed into reams of loo paper so it could withstand the bumpy journey back to Koobi Fora. Back at camp, I would often get to spend time reconstructing these tantalizing puzzles of broken bones into more complete specimens. My search image, initially restricted by my focus on primate anatomy, rapidly expanded as the richness of the Koobi Fora sediments yielded species after species in the bountiful fossils we were finding and retrieving.

  If we found something that needed time and patience to excavate, we would generally return later with additional tools. Very fragile specimens needed to be encased in plaster of paris. “The sacking has to be wet before you start or it doesn’t adhere properly,” Richard explained. “And if the fossil is heavy, you need to use sticks to build in supportive braces to protect the fossil.” The plaster of paris dried quickly, and I was soon adept at judging the correct amount and consistency to help prepare these packages for their journey back to Koobi Fora and then to Nairobi.

  We carried water in the vehicles but not in our field bags, so by the end of the morning, we were always ready to return to the vehicle for a drink and some shade. In those days, no one had made the connection between sun and skin cancer; we wore the minimum of clothing and used no sunscreen, and I never wore a hat. Lunch was sparse, usually a few slivers of dried meat from a tiang that Richard had reluctantly shot and dried in the sun earlier. We often ate under the shade of an acacia tree on the bank of a dry sand river, or if we returned to the base camp by the lake, we enjoyed a more gourmet lunch depending on the camp’s supplies. We discussed the morning’s discoveries over this repast, and the field crew would always have something to show us in the afternoons. Although temperatures were normally in the high thirties or low forties (Celsius), we became used to the heat, and for much of the morning, there was usually a welcome cooling wind. After lunch, we would gratefully rest for an hour or two until the heat began to lessen.