One Sunday in late August Tyler took a day off, rented a dinghy and outboard motor, and went fishing near Flint Island up the coast from the little lakeside village of Schreiber, Ontario. As he cast and reeled his line, he spotted an odd-looking outcrop of Gunflint rocks on the nearby shore. He pulled the boat onto the rocky shingle (a site later dubbed the "Schreiber Beach Locality") and took a look.
The flat shelflike outcrop, extending a few tens of meters back from the water's edge, was slightly inclined, sloping gently into the lake. Tyler recognized immediately that this was a bedding plane exposure--glaciation of the great Ice Age and countless Lake Superior winters had stripped away overlying strata, bringing to view the upper surface of a half-meter-thick bed of dense, fine-grained chert, a typeof sedimentary rock composed of interlocking grains of the mineral quartz, SiO2. But the rocks were unlike the rusty-red, iron-rich cherts typical of Gunflint beds elsewhere. These were jet black, and their distinctive waxy, glasslike luster suggested the quartz grains that made them up were extremely small. He was further surprised to see that the chert bed was packed with dozens of closely spaced Cryptozoon-like mounds, some more than a meter across, each built up of a nested series of more or less concentric thin wavy layers. Clearly, these iron-lacking black cherts were unusual. Though Tyler was chiefly interested in the iron-bearing beds of the formation, he collected several hand-sized specimens from the outcrop.
Whether Tyler landed any lake trout that afternoon is unknown, but the distinctive jet black cherts he bagged on this fateful outing would soon prove a remarkable catch.
When he returned to his laboratory at the end of the field season, Tyler selected a suite of rock samples to be prepared for further study. Each specimen was sliced into millimeter-thin slabs, which were then cemented onto glass microscope slides and ground to a waferlike thinness--preparations, known as petrographic thin sections to be studied using a high-powered microscope. The iron-poor black cherts from Schreiber Beach were almost an afterthought, but as he had suspected at the outcrop he found them to be composed of exceedingly tiny quartz grains, the largest only a few micrometers (one thousandth of a millimeter) in size. This meant that unlike the Gunflint strata to the far west, in northern Minnesota, those at Schreiber Beach had escaped the pressure-cooking of geologic metamorphism, in Tyler's phrase "providing a glimpse through the Precambrian metamorphic veil."
He solved easily the question of their black color, for in the thin sections he could see that the rocks contained abundant cloudlike clumps and wispy layers of microscopic particles of dark brown to black coaly organic matter. The rocks looked like a chertified very thinly layered deposit of black coal. But he was mystified to discover that each thin section was packed full of layer upon layer of tens of thousands of clearly defined, uncompressed, long, thin, threadlike filaments and tiny, hollow, balloonlike balls. Never before had he seen anything like this!
Tyler was an expert mineralogist. He was sure that the minute brownish threads and spheres were not mineral grains. And in the thin sections he could see that the tiny objects were totally embedded in the cherts, enclosed on all sides by quartz grains, so they certainly were not microscopic contaminants introduced in the laboratory. But if they were neither mineral grains nor laboratory contaminants, what were they? Their texture and dark brown color suggested that they were composed of coal-like organic matter. If so, the sinuous interwoven strands and small hollow balls were likely to be some sort of microscopic fossils. This was a total surprise.
Questions raced through Tyler's mind. The mid-Precambrian age of the Gunflint rocks seemed established beyond question. If these really were microscopic fossils, he had made a stupendous discovery. But how could he be sure? Perhaps the "fossils" were merely soil microbes that had somehow worked their way into minute cracks and fissures in the cherty sediments. Or maybe they were a fluke, some type of purely mineralic oddity he simply didn't know about. And if they actually were fossils, what type of fossil organisms might they be? He checked the textbook from the one paleontology course he had taken during his student days at the Massachusetts Institute of Technology (MIT), but he was unable to find anything that even remotely resembled the tiny threads and spheres.
Tyler vacillated between being pleased and puzzled. All of his experience and all of the evidence he could muster indicated that the distinctive microscopic objects were not mineral, that they must be ancient fossils. This was his best guess. But it was only a guess. He was a mineralogist--not a biologist, not a paleontologist--and he was determined not to climb out on this shaky limb without getting expert confirmation.
Early in the fall of 1953, only a few weeks later, Tyler took with him photographs of his microsopic finds when he journeyed to Boston to attend the national meeting of the Geological Society of America, a yearly gathering of several thousand professional geologists for the purpose of exchanging ideas and renewing old friendships. There, at the MIT cocktail party, he sought out Robert Shrock, his old paleontology professor (and co-author of the one paleontologic textbook Tyler owned) and showed him pictures of the Gunflint "fossils." Immediately, Shrock became excited. After only a few moments he not only was convinced that the objects were true microfossils but had identified them as parts of simple fungi--the slender filaments asthe tubular vegetative bodies of the organisms and the small cell-like spheres as reproductive spores. As Shrock told me years later, they were "exactly the sort of fungi that cover the top of a jam jar left open too long."
Shrock was a highly distinguished paleontologist, known worldwide, but because he was an expert on fossil animals (especially invertebrates, those without backbones, like corals and clams) he felt it important to have his assessment firmed up by someone knowledgeable about ancient plants. As luck would have it, Shrock knew exactly the right person. Elso S. Barghoorn (1915-1984), a bright young paleobotanist, had just recently been appointed to the biology faculty at Harvard, a short sprint up Massachusetts Avenue from MIT. Not only did Barghoorn know about plant fossils and geology, prerequisites for interpreting Tyler's fossil-like objects, but he also was a fungal specialist, an expertise he had developed in Panama during the Second World War when he studied the microscopic filamentous fungi that were fouling binoculars and other military equipment in the Pacific theater.
With Tyler in tow, Shrock headed toward the Society's Harvard cocktail party to find Barghoorn. By chance, halfway there, theymet Barghoorn in the lobby of the Statler Hotel. The three--Tyler, Shrock, and Barghoorn--sat, chatted, and plotted a research strategy.
By mid-January, a few months later, Tyler had sent Barghoorn several photographs and a one-paragraph summary of his research results. Barghoorn fleshed this out with a set of biologic interpretations, and their short manuscript reporting the discovery of the Gunflint fossils was published in the April 30, 1954, issue of Science, the journal of the American Association for the Advancement of Science.
This was a very sketchy report, assembled in great haste, and it is perhaps not surprising that though "five morphologically distinct" types of fossil organisms were said to have been identified (one kind of flagellated protozoan, two types of algae, and, following Shrock's lead, two types of fungi), only one of these--a form compared with "algae" (cyanobacteria) of the genera Lyngbya and Oscillatoria--has stood the test of time. And in order to avoid the still smoldering controversy about the origin of Cryptozoon, they elected not to mention that the densely packed fossils were found within and actually made up the concentrically stacked layers of Cryptozoon-like mounds (an association that, once recognized, would prove pivotal to the development of the field). Nevertheless, this article on "the oldest structurally preserved organisms that clearly exhibit cellular differentiation and original carbon complexes which have yet been discovered in pre-Cambrian sediments," was a benchmark, a monumental "first."
Timofeev was a burly bear of a man, but more of a disheveled teddy bear than the growling Soviet bear pictured in much of the noncommunist world. He was a gracious host, both in his laboratory and his small apartment, and in his office (with the door closed) he delighted in serving visitors tumblers of 200 proof lab alcohol laced with one or another of the flavored tinctures kept under lock and key in his desk drawer. A Ukrainian by birth and of friendly demeanor, he had risen by dint of effort--despite an earlier stay in one of the infamous gulags--to become head of the Precambrian Paleontology Laboratory of his institute, a position of considerable responsibility.
In thin sections, like those studied by Tyler and Barghoorn, fossils are detected within the rock, entombed in the mineral matrix, so the possibility of laboratory contamination can be ruled out (see plates 1 and 2). But preparation of thin sections requires special equipment, and their microscopic study is tedious and time consuming. A faster technique, pioneered for Precambrian studies in Timofeev's lab, is to concentrate the fossils by dissolving the rock in mineral acid (hydrochloric acid for limestones, hydrofluoric for cherts and siltstones). Because of their coaly composition, the organic-walled microfossils pass through the technique unscathed. Abundant fossils are concentrated in the resulting sludgelike acid-resistant residue (known technically as a palynological maceration) which can be slurried onto a microscope slide for study (see plates 3 and 4).
Unfortunately, the maceration technique (patterned after that employed by Soviet petroleum geologists to extract fossil pollen and spores from Phanerozoic shaley rocks) is subject to error-causing contamination. Contaminants can be introduced at almost every stage of the process. At the beginning, even though rock surfaces are cleaned with care to remove sticky soil, microbes in tiny rock crevices are likely to be missed. Laboratory water and commercially available mineral acids can also contain a zoo of living contaminants--bacteria, cyanobacteria, unicellular algae, microscopic fungi. And an almost limitless array of fossil-like objects can be introduced during transfer of the residue onto microscope slides. Common culprits include dust, cigarette ash, spores, and pollen grains that settle from the lab air; lint fibers from clothing or the cloth used to clean microscope slides; small woody fragments and chunks of resin abraded off the wooden rods used to stir the acid-rock sludge; flakes of dandruff and strands of hair; even bits of small bugs (evidently, parts of spiders that live in water pipes).
From the 1950s into the 1970s, as studies of the Precambrian fossil record were getting under way in earnest, all of these maceration-borne contaminants were misinterpreted as fossils by one worker or another. But it is important to remember that during these years, the true nature of Precambrian life was utterly unknown. There was no established fossil record with which to compare new finds. No one knew what to expect. Mistakes were easy to make and Timofeev's laboratory was not immune. Moreover, though Timofeev had sound geologic training and a lot of field experience, his biologic background was wanting. Yet he had no chance to fill in the gap--for years he was practically the only Soviet worker in the field, and because of his Gulag past his correspondence with foreign scientists was closely monitored, contact with foreign visitors restricted, and travel outside the Soviet Union prohibited.
Viewed in this light, it is no wonder that much of Timofeev's early work was less than sterling. Some of the "fossils" he reported were contaminants. Others were Phanerozoic rather than Precambrian in age. Still others were algal phytoplankton, not spores of land plants as he had initially supposed. And because publishing photographs at that time in the USSR was nearly impossible for those who werenot members of the scientific elite, practically all of Timofeev's early studies were illustrated by his own line drawings, a form of presentation notoriously subject to self-delusional "fact fudging."
The 1950s, the early days of Timofeev's work, spanned the height of the Cold War. In the United States, Joseph R. McCarthy, the frenetic junior senator from the state of Wisconsin, led the charge to cleanse the country of communists, pinkos, and so-called fellowtravelers. President Eisenhower and the American Congress set aside funds to build the interstate superhighway system, prodded by the notion that it would serve as an escape route from urban centers during nuclear attack. Schoolchildren were taught to "duck and cover." Television, a new addition to affluent homes, overflowed with warnings of the "Red Menace." In the West, things Soviet were viewed with distrust. Soviet science was no exception (to many a view well justified by the earlier Lysenko fiasco in Soviet genetics), and the antipathy could be deep seated. Barghoorn, for instance, refused ever to visit the Soviet Union and was loathe even to acknowledge Soviet scientific articles in his research reports. (This position understandably became rock solid in the early 1960s when his brother, Frederick, a Yale social science professor, was imprisoned in Moscow as an alleged spy, and finally freed--after two weeks of sleep-deprived interrogation--as a result of repeated personal pleas by President Kennedy to Chairman Khrushchev).
Ultimately, of course, firmly established facts win out in science. But in the short run, acceptance of a new idea can be influenced decisively by the prevailing political climate and the prestige of the scientist proposing it. Whether right or wrong, on the mark or not, the views of Darwin, Dawson, Walcott, and Seward all received respectful hearings because they were espoused by internationally recognized luminaries, and Barghoorn's position at Harvard added a telling air of authority to the Tyler-Barghoorn report of fossils in the Gunflint chert. In contrast, neither Timofeev, his work, his laboratory, nor his institute was well known beyond the boundaries of the Soviet Union, and acceptance of his views in the West was poisoned by international politics. Though some of Timofeev's work was flawed, a large part has proved sound and the technique he pioneered to discover microfossils in Precambrian shaley rocks is now used worldwide. Yet in the 1950s it probably would not have mattered had Timofeev discovered the Rosetta Stone of this or any other science. Beyond the confines of the Iron Curtain, some would have found reason to doubt his claims, no matter what!
Born in West Upton, Massachusetts, Cloud worked his way up from modest beginnings. Perhaps because of this he was feisty, a fighter figuratively and evidently literally as well. He is said to have been bantamweight boxing champion of the American Pacific Scouting Force during World War II, and though I cannot vouch for the claim, the image fits. He was a person who sought to dominate, a no-nonsense leader who did not suffer fools gladly. He once told me that when he was appointed chief of the Paleontology and Stratigraphy Branch of the U.S. Geological Survey in 1949, he had his chair and desk placed on 4-inch-high risers so he could look down on those coming to him to plead their cases--a position of authority he was convinced helped him do his job. His 10-year stint in this post was notably successful as he doubled the number of geologists in the branch and raised it to a level of scientific preeminence never seen before or since.
At work, Cloud was not given to idle chatter and struck some colleagues as a bit imperious (one of them referred to him as "the little general," though never to his face). Yet Cloud had an overriding saving grace. He was brilliant! His Precambrian interests were first evident in the late-1940s when he argued in print that though the known Early Cambrian fossil record was woefully incomplete, it was the court of last resort and, ultimately, the only court that mattered. Cloud's view was that any and all notions regarding the Cambrian explosion of many-celled animals should be based on painstaking examination of the fossil record as known, on directly available hard data rather than mushy wishful thinking.
In the 1960s, Cloud became much more active in the field, writing a major paper that to many certified the authenticity of the Tyler-Barghoorn Gunflint microfossils. Later he authored a series of reports adding new knowledge to the Precambrian record of microbial life. But Cloud's interests were broad and eclectic. He was a geologist to the core and knew that the rock record held the key to understanding the evolution not only of life but of the Earth's environment. And he was a gifted synthesist, showing his mettle in a masterful paper of 1972 ("A Working Model of the Primitive Earth"), where he set the stage for modern understanding of the interrelated atmospheric-geologic-biologic history of the Precambrian planet.
Preston Cloud was a true giant in the development of Precambrian paleobiology.
Born on Christmas day in 1906 in northwestern Bohemia, Glaessner was educated at the University of Vienna, where he earned doctorate degrees both in law and in science (like Charles Lyell, he supposed that income from the practice of law might be needed to support his early-found passion for natural history). By the time he received his second doctorate, at the age of 25, he had already published nearly a score of scientific articles and was invited to Moscow to organize research in micropaleontology for the Petroleum Research Institute of the Soviet Academy of Sciences. There, in 1933, Glaessner met the ballerina Tina Tupikina. They were wed 3 years later and, spurred by the Soviet regime's dictum that foreign specialists must either take up USSR citizenship or leave, he and his young wife departed Moscow for Vienna in 1937.
Only a few months later Hitler's army occupied Austria. With the help of friends in London, Glaessner and his wife were soon again on their way, this time to Port Moresby, New Guinea, where he was to organize a micropaleontological laboratory for the newly formed Australasian Petroleum Company. And when war came to New Guinea in 1942, the Glaessners fled once more, this time to Australia.
In 1946, Glaessner was awarded his third doctorate, honorary doctorate of science at the University of Melbourne, and in 1950 he joined the faculty of the University of Adelaide.
Three years before Glaessner was appointed professor at Adelaide, Reginald C. Sprigg announced his discovery of fossils of primitive soft-bodied animals, chiefly imprints of saucer-sized jellyfish, in the Ediacara Hills of South Australia. Though Sprigg first thought that the fossil-bearing beds were Cambrian in age, Glaessner showed themto be Precambrian (albeit marginally so), the oldest fossils of multicelled animals known to science. Together with his colleague, Mary Wade, Glaessner spent much of the rest of his life working on this benchmark fauna, bringing it first to international attention in a Scientific American paper of the early 1960s, and later in a landmark monograph, The Dawn of Animal Life, that appeared in 1984.
With Glaessner in the fold, the stage was set. Like a small jazz band--Tyler and Barghoorn trumpeting microfossils in cherts, Timofeev beating on fossils in siltstones, Cloud strumming the early environment, Glaessner the earliest animals--great music was about to be played. At long last, the curtain was to rise on the missing record of Precambrian life!
For some reason, now lost to me, the matter struck me as extraordinarily intriguing. I had been brought up in a family of scientists (my mom was schooled in botany and mathematics, my dad was a paleobotanist), and there was no doubt in my mind that Darwin was right. Evolution was a fact, so there simply had to be a Precambrian fossil record. Its absence might have been "inexplicable" to Darwin, but I soon became determined that it would not be so to me.
At that time, Oberlin had probably the largest small-college library in the world. I read everything I could find about Precambrian life. The more I read the more enamored I became, and within a few months completed a forty-page essay on the subject (a sophomoric synthesis which, remarkably, turned out to be the outline for my life's work). I was particularly taken by a passage in a slim 1949 volume by the renowned evolutionary biologist George Gaylord Simpson. Simpson argued that because the evolutionary distance between humans and trilobites seemed roughly the same as between a trilobite and an amoeboid protozoan (then thought to be among the earliest forms of life), and because the oldest trilobites were about 500 Ma in age, then the first amoebas--and thus the origin of life itself--must date from about 1,000 Ma ago. This would mean that the origin of life had required an enormously long period--billions of years. But to Simpson this made good sense because he thought that the distance between non-life and the first organisms must be vastly greater than between any two types living today.
Clearly, a lot of this was guesswork. But if Simpson's notion was even close to being right, it told me that all I had to do was to trace back the fossil record to about 1,000 Ma ago, where I might then expect to find direct evidence of life's beginnings. I was young, naive, and full of enthusiasm. This was wonderfully heady stuff. I was sold!
Isolated on that outcrop in the midst of a swirling downpour, we began to chat, Chaloner asking me about my plans. With heartfelt enthusiasm, I told him about my bold hopes to uncover the missing Precambrian record of life. Though only a recent Ph.D., Chaloner was experienced and worldly (and has since become Britain's most distinguished paleobotanist and a fellow of the Royal Society). And, like all British paleobotanists (indeed, like paleobotanists worldwide), Chaloner was thoroughly schooled in the writings of A. C. Seward. He began his reply gently, thoughtfully, telling me that this was "a good problem" but that he "wanted me to succeed," and since this question had gone unanswered for more than a century it would be "prudent" for me to approach it with "caution."
His kind advice was plain--after graduating from college I should earn a master's degree and a doctorate (working on some "potentially solvable scientific problem") and then find appointment as an assistant professor, which, if all went well, would lead to a tenured position on a university faculty. As a tenured professor, I would be free to work on anything that interested me, even something that stood such an astonishingly slim chance of success as finding Precambrian fossils.
I quickly tallied up the years--college (2 1/2 to go), graduate school (probably 6), and assistant professor (6 more). I was 18 years old, and Chaloner was proposing that I wait another 14 or more years--almost my whole lifespan!--then, "if all went well," I could finally embark on my quest. My dream was crumbling before my eyes!
Both treated me with kindness, and Barghoorn even gave me chunks of the Gunflint chert which I sectioned and used as the subject of my Oberlin honors thesis. In the summer of 1963, a fresh college graduate, I entered Harvard as Barghoorn's student.
My goal at Harvard was to expand my undergraduate thesis into a Ph.D. dissertation on the Gunflint microfossils. During my first year, however, I got sidetracked working with Barghoorn and Warren G. Meischein, a world-class organic geochemist then employed at the Esso Research Laboratories in Linden, New Jersey, on a broad paleobiologic study of a 1,000-Ma-old shale deposit in northern Michigan. For me this turned out to be a wonderful education, but it gobbled up all of my time until our long manuscript was finally completed in August 1964. With the academic year about to begin, Barghoorn's plan to complete a second manuscript that summer, for the first time describing in detail the Gunflint microfossils, was put on hold.
Nothing of note had been published on the Gunflint fossils since the announcement of their discovery a decade earlier, in 1954, but in the interim much had transpired. Tyler's pioneering work had continued apace, and with support pouring in from the National Science Foundation he had employed several students in his laboratory at the University of Wisconsin who worked tirelessly, finding and photographing the tiny microscopic fossils. Diverse types of microorganisms had turned up, all new to science and some quite bizarre.
By 1958, Tyler had put the finishing touches on a detailed description of the geologic setting, mineralogy, and paleoenvironment of the Gunflint deposit and had forwarded the text, along with photographs of the fossils, to Barghoorn, whose task it was to interpret, formally describe, and officially name the newly discovered life-forms. But during the mid-1950s Barghoorn's personal life had taken a turn for the worse, and in the years since 1958 he had been unable to carry out his part of the job. Then, tragically, Tyler fell ill, and at the age of 57, in October 1963, he died, never to see the ripened fruits of his labor reach the printed page. Barghoorn traveled to Madison, Wisconsin, and brought back to Harvard Tyler's field notes, rock specimens, lab records, thin sections, and a huge number of photographs. I was given the task of sorting through this maze, of organizing the research materials of a senior scientist whom I much admired but had never met.
In their initial 1954 report of the Gunflint discovery, Tyler and Barghoorn had craftily neglected to pinpoint the location of their find (noting only that it was "near Schreiber" in "southern Ontario"), but Cloud ferreted it out. (I learned later that Cloud had traveled to Schreiber, rented a boat, found the fossil locality, and was stranded on the outcrop for three days by a fierce Lake Superior storm--a forced sojourn during which he carried out the first truly excellent detailed geologic study of the local area.)
The manuscript Barghoorn shoved into my hands had been submitted to Science, whose editor, Philip Abelson, had sent it to Barghoorn for scientific review in preparation for its publication. Barghoorn was more than a little agitated. He was livid. After all these years, he was about to be scooped!
Fuming, Barghoorn scurried around trying to locate the shelved 1958 Tyler text. I was assigned the task of preparing the review of Cloud's paper (and though I took pains to do the most thorough job I could, I discovered later that Cloud--no doubt thoroughly annoyed by the situation--ignored every one of my suggestions). By the end of the next day, after I had finished writing the review, Barghoorn had come up with a plan of attack: we would hold Cloud's manuscript for a week or two and use that time to get the Tyler-Barghoorn paper in publishable shape. Then Barghoorn would call the Science editor, Abelson, explain this "serendipitous coincidence" of timing, and convince Abelson to publish the Tyler-Barghoorn paper first, thereby retaining for them their claim of scientific priority.
The next two weeks were unbelievably hectic. Barghoorn had no courses to teach that semester and, as instructed, I cut all my classes. Tyler's research materials were a shambles, and by that time I had managed to sort through only about a third of several huge piles. Moreover, I had found to my horror that though the photographs were keyed to individual thin sections, there was no information to pinpoint the specific location within each section (the microscope stage coordinates) where Tyler's students had found the pictured fossils. This meant that I would have to spend many weeks, maybe months, scanning section after section in order to relocate the photographed specimens. Worse than trying to find numerous needles in multiple haystacks, given our time constraint there was no way this could be done.
Clearly, we would have to rely on what we already had on hand. That meant that Barghoorn's interpretations and descriptions of the fossils, and the naming of them (that is, the taxonomy of the Gunflint assemblage), would have to be based on the best photographs available rather than on examination of the individual specimens. (This, I am sorry to say, was not good science. No one, ever, should interpret, describe, and name new organisms without studying carefully the specimens themselves. It's true that we were forced into this by unusual circumstances, but this was not the proper way to do this job.)
At the beginning of each day, I would rummage through the photos and pick out the "best" for any given size-shape category (thin filaments, fat filaments, small spheres, big spheres, umbrella-shaped forms, and so forth), and then within each category would pile together those that to me looked most alike. Barghoorn would then check and revise my groupings and begin writing the formal taxonomic descriptions. By this time, he would have begun to for mulate an appropriate Greek or Latin name for each morphologically defined genus (for example, Gunflintia, for the slender filaments, named after the geologic deposit; and Eoastrion, "dawn little star," for radiating filament clusters), names that I was sent to try out on Leslie Garay, the orchidologist down the hall who was an expert on such matters.
Barghoorn was working feverishly, as was I, and when he left at the end of each day I had the night job of preparing high-quality prints of each of the photographs selected, pictures that I could then paste together to make up figures to accompany the final published manuscript.
After nearly two weeks of this frantic activity, the job was nearing completion. Barghoorn had finished writing his portion of the text and the formal descriptions of the various types of fossils, and though I had not yet completed the final figures I did have good prints of practically all the photos to be included. It was now time to call Abelson at Science. But before that, the matter of authorship of the paper had to be sorted out.
In scientific circles, the authors of the first published paper of any series of papers that report similar new finds are credited with the discovery, establishing for its authors scientific priority, a sort of intellectual "ownership" rather like that gained from patenting a new invention. In the same way, in any multiauthored scientific work, the order of authorship makes some difference because the first (primary, principal, or senior) author is assumed to have contributed most to the project and, thus, to deserve the lion's share of the credit.
In this case, Tyler had discovered the deposit, recognized its significance, and (with his students) done most of the scientific work. Clearly, Tyler deserved the majority of the credit and both heand Barghoorn had always assumed that this magnum opus, like their 1954 paper on the Gunflint find, would have Tyler as the first author, Barghoorn the second.
But Tyler was now deceased. Barghoorn broached the subject, wondering, "What should we do?" I knew what he wanted me to say, and as his student I certainly wanted to please him. Still, I believe my reply was honest. I argued that the paper was bound to raise questions, that some might doubt the authenticity of the Gunflintfossils, and that because Barghoorn had interpreted, described, and named the new fossil microorganisms he obviously would have to take the heat. Someone had to stand up and be counted, and Barghoorn was the only one who could assume that responsibility. He seemed pleased by my response.
With the Barghoorn-Tyler order of authorship settled, he theninvited me to join them as the third (junior) author of the paper. I thought the world of Professor Barghoorn, and though he had been kind to me before, this gesture was unbelievable! Still, I knew that I simply had not contributed enough to deserve such an honor. Respectfully, I declined.
(Over the years since I have wondered somewhat wistfully how my career might have soared had I accepted Barghoorn's generosity. The Barghoorn-Tyler paper is a classic. For all of time it will probably stand as the most important article ever written in the field, and it certainly would have made an impact on my life had it been by Barghoorn, Tyler, and Schopf! But credit matters in science, and it would have been wrong for me to have authored a work to which I contributed so marginally. I do, however, deeply value Barghoorn's published acknowledgment to me in the paper "for assistance . . . in taxonomic description" and I take personal pride in his use of a couple of the photographs from my undergraduate honors thesis, pictures of the Gunflint fossils that he regarded as among the best available.)
All was now in place to contact Abelson at Science. Barghoorn invited me into his office and made the call. Immediately, he found out that Cloud, too, had recently called Abelson, inquiring about the fate of his presumably "lost manuscript" for which Cloud had yet to receive prepublication scientific reviews.
Barghoorn assured Abelson that the review (mine) was completed and would soon be sent, and he then gave Abelson the story: "As luck would have it, I have a manuscript ready to submit on the same material . . . you know, the one I've been working on for years. As you may recall, Tyler and I announced our discovery in Science--your journal [sic!]--ten years ago. It would be only fair for us to have priority . . . our paper ought to be published first."
Abelson was a remarkable man, a first-rate chemist and an exceptionally gifted geologic-biologic scientist (though a disappointing public speaker, as I first discovered when I journeyed to Cleveland to hear him in my undergraduate days). As editor of Science, he had taken this formerly run-of-the-mill journal to a position of international prominence. Moreover, he was well acquainted with, knew the personalities of, both Barghoorn and Cloud; he knew the history and importance of the Gunflint discoveries; and, in June 1961, at a small scientific meeting held at the Blue Meadow Lodge in the Blue Ridge Mountains of Virginia, he had heard Barghoorn publicly announce,in Cloud's presence, that the Tyler-Barghoorn Gunflint paper would "soon be ready."
Abelson wanted no part of what seemed to him a brewing donnybrook. He wisely withdrew from this potential mess by making a deal with Barghoorn: "You talk with Pres Cloud. Whatever you two work out will be OK with me."
I still stood beside Barghoorn's desk as he telephoned Cloud. "Hello, Pres. Received your manuscript for review. With a few minor changes, it looks just fine. But, hey, as luck would have it, my paper with Stanley is finally ready to go. Really! I have it in my hands right now. It goes out tomorrow." Cloud said: "Seeing is believing!" (and Barghoorn covered the receiver and repeated to me: "He says, seeing is believing"). "You know, Pres, Stanley and I worked for years on this--our paper ought to appear in Science first. What do you say?" Cloud said: "Seeing is believing!" (again, Barghoorn repeated to me: "He says, seeing is believing").
The Barghoorn-Tyler manuscript, accompanied by my yet unfinished plates, was mailed to Cloud the next morning. By the time we had heard from him a week or so later, the final draft and finished plates were ready to submit to Science. Cloud was more than a little miffed, but he swallowed his pride and okayed Barghoorn to publish first. The two papers appeared in Science in 1965, the first in early February, "Microorganisms from the Gunflint Chert" by Barghoorn and Tyler, followed a few weeks later by Cloud's article, "Significance of the Gunflint (Precambrian) Microflora." Landmark papers they were!
(To an outsider, the Barghoorn-Cloud battle over who could scoop whom must appear unseemly, even tawdry. And, of course, it is. But science is done by real people, and it's much more competitive than one might expect. Most turf fights never come to light--or like this one lie hidden for decades--but though they don't happen every day, they are not too uncommon. Probably the most famous centered on "Darwinian" evolution. Darwin gathered his evidence as the naturalist on the voyage of H.M.S. Beagle and by 1840 had put the finishing touches on a manuscript unveiling his idea of the "struggle for existence . . . descent with modification." But he was loathe to submit his article for publication, and it was not until early in 1858, nearly 20 years later, that he finally was spurred to action by seeing the very same idea in a manuscript sent him by British naturalist Alfred Russel Wallace (1823-1913) in the hope that Darwin would forward it for publication. On July 1 of that year the two received equal billing, their ideas presented back-to-back at a special meeting of the Linnean Society in London. Yet we remember Darwin, not Wallace, partly because only a year later On the Origin of Species appeared--thick with supporting facts, observations, even examples from everyday life--but also because Darwin belonged to the scientific elite and was in London, the seat of scientific authority, while Wallace was far afield, naturalizing in the wilds of the Malay Archipelago.)
Within weeks, Barghoorn had received numerous invitations from colleges and universities to speak on the new finds. There was too much for him to handle alone so a certain number of these invites trickled down to me. This was a treat. I hadn't before done much public lecturing and I was lucky to have this chance. Moreover, though I was only a second-year graduate student I was gaining terrific exposure, making contacts that were certain to come in handy when it became time to look for a job.
Soon after I hit the lecture circuit, however, I was introduced to a reality I had not expected. Despite the evidence now amassed, the two landmark papers (not to mention my own honor's thesis, which hardly anyone knew about) and the undoubted prestige of Barghoorn, Cloud, Science, and Harvard, I was shocked to see the rampant skepticism. Bill Chaloner was right--this was a field in which "prudent caution" was very much required!
Dawson's debacle, the Cryptozoon controversy, Seward's criticism--all these were object lessons that had been handed down from professor to student, generation to generation, and all had become part of accepted academic lore. Barghoorn had known this for years (a factor, I now realized, underlying his reluctance to get the Gunflint project off the back burners), and it was now my turn to learn it firsthand.
The big problem was that the Gunflint organisms stood alone. They were isolated in time, seemingly marooned in the remote Precambrian, removed by nearly a billion and a half years from all other fossils known to science. Many of the old questions and quite a number of new ones came to the fore. Perhaps the deposit had been misdated and was not Precambrian at all. Perhaps the "fossils" were soil contaminants that had entered the rock through now-sealed cracks and crevices. Or maybe the tiny objects were simply needle- and ball-shaped mineral grains. Or bubbles in the rock. Or artifacts of thin-section preparation. Or some crystalline oddity associated with the formation of chert. Moreover, if Cryptozoon was "known" to be nonbiologic, weren't the Cryptozoon-embedded filaments and spheres suspect too? Why hadn't cellular fossils turned up in other Cryptozoon-like structures, not even in the Phanerozoic?
Couldn't this whole business be some sort of fluke, some hugely embarrassing, awful mistake?
Once the Gunflint paper had been finished, Barghoorn turned the chunks of Australian rock over to me to see what I could find. I laboriously prepared half a dozen thin sections and was elated (to put it mildly) to discover they were full of microscopic fossils. There were many new types of filaments, spheres, and colonies of clustered cells, many that closely resembled living cyanobacteria (Walcott's "algae"). The new fossils were better preserved, much better preserved than those in the Gunflint rocks. I could see distinct cell walls, colony-encompassing mucilage sheaths, remnants of cell contents, everything! For a few weeks I was the lab hero. And though the age of this Precambrian deposit (the Bitter Springs Formation) was known only approximately, it seemed likely that it was about 1,000 Ma, roughly half as old as the Gunflint chert.
With care I crafted a plate of photos and drafted a short manuscript--the very first scientific paper I put together all by myself. Barghoorn and I sent the paper off to Science. Its publication latethat summer--now viewed in the context of the earlier landmark articles on the Gunflint organisms--heralded the birth of a new field of science.
This second find showed that the Gunflint fossils were no fluke. Indeed, probably the only truly odd thing about the Gunflint and Bitter Springs fossils is that similar deposits had not been discovered even earlier. Walcott and a few others in his time had started the train down the right track only for it to be derailed by Seward, Raymond, and skeptics of their ilk. But like Darwin, all had assumed the tried and true techniques of the Phanerozoic hunt for large fossils would prove equally rewarding in the Precambrian. Simply put, this was wrong.
The Gunflint and Bitter Springs articles of 1965 charted a new course, showing for the first time that a search strategy specifically focused on the peculiarities of the Precambrian fossil record would pay off. The four keys of the strategy were to search for (1) microscopic fossils in (2) black cherts that are (3) fine-grained and (4) associated with Cryptozoon-like structures. Each part was crucial.
As the field has soared, new strong pillars have been added toits sound foundation. The Barghoorn-Tyler studies of Cryptozoonforming microbes have been expanded by work on living microbial communities and of particular biochemicals (the nucleic acids of protein-manufacturing ribosomes) that place these microorganisms on early branches of the Universal Tree of Life. Timofeev's pioneering finds of fossil plankton in siltstones have been enlarged to reveal the first extinctions in the history of life and the rapid rise of new biologic types that accompanied the advent of sexual reproduction. Cloud's benchmark environmental syntheses, strengthened by a new understanding of comparative planetology, atmospheric evolution, andcarbon isotope-based evidence of the history of photosynthesis, have been sharpened and refined to reveal an increasingly focused picture of the developing early Earth. And Glaessner's early studies of Precambrian animal fossils have grown into a global blizzard of activity that has provided new insight into the classic Precambrian-Cambrian boundary problem: the previously mysterious abrupt rise of Phanerozoic multicelled life.
More than 99% of all scientists who have ever investigated the Precambrian fossil record are alive and working today. Discoveries are being reported at an ever-quickening clip, literally worldwide by workers in Australia, Brazil, Canada, China, England, France, Germany, India, Israel, Japan, Lithuania, Mexico, Russia, South Africa, Sweden, and the United States. This is not the place to list an honor roll of active Precambrian workers and their myriad achievements. I hope that I will be forgiven this omission but my colleagues will know, as do I, that this book is based on our collective contributions to the science and that all of us working today sit atop the broad shoulders of the few bold scientists who blazed this trail in the 1950s and 1960s, just as their course was set by the Dawsons, Walcotts, and Sewards, the pioneering pathfinders of the field.
The collective legacy of all who have played a role dates to Darwin and the dilemma of the missing Precambrian fossil record that he first posed. It is a great joy that after more than a century of trial and error, of search and final discovery, what was once "inexplicable" to him is no longer so to us.