. "2 Solution to Darwin's Dilemma: Discovery of the Missing Precambrian Record of Life." Variation and Evolution in Plants and Microorganisms: Toward a New Synthesis 50 Years after Stebbins. Washington, DC: The National Academies Press, 2000.
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Variation and Evolution in Plants and Microorganisms: TOWARD A NEW SYNTHESIS 50 YEARS AFTER STEBBINS
ated enormous interest. Yet it soon became apparent that acceptance of ancient life would come only grudgingly. The well had been poisoned by Dawson's debacle, the Cryptozoon controversy, Seward's criticism—object lessons that had been handed down from professor to student, generation to generation, to become part of accepted academic lore. Moreover, it was all too obvious that the Gunflint organisms stood alone. Marooned in the remote Precambrian, they were isolated by nearly a billion and half years from all other fossils known to science, a gap in the known fossil record nearly three times longer than the entire previously documented history of life. Skepticism abounded. Conventional wisdom was not to be easily dissuaded. The question was asked repeatedly: “Couldn't this whole business be some sort of fluke, some hugely embarrassing awful mistake?”
As luck would have it, the doubts soon could be laid to rest. During field work the previous year (and stemming from a chance conversation with a local oil company geologist by the name of Helmut Wopfner), Barghoorn had collected a few hand-sized specimens of Precambrian stromatolitic black chert in the vicinity of Alice Springs, deep in the Australian outback. Once the Gunflint paper had been completed, I was assigned to work on the samples, which quite fortunately contained a remarkable cache of new microscopic fossils, most nearly indistinguishable from extant cyanobacteria and almost all decidedly better preserved than the Gunflint microbes (Fig. 4). Although the age of the deposit (the Bitter Springs Formation) was known only approximately, it seemed likely to be about 1,000 million years, roughly half as old as the Gunflint chert.
Barghoorn and I soon sent a short report to Science (Barghoorn and Schopf, 1965), publication of which—viewed in light of the earlier articles on the Gunflint organisms —not only served to dispell lingering doubts about whether Precambrian fossils might be some sort of fluke, but seemed to show that the early fossil record was surprisingly richer and easier to unearth than anyone had dared imagine. Indeed, it now appears that the only truly odd thing about the Gunflint and Bitter Springs fossils is that similar finds had not been made even earlier. Walcott had started the train down the right track only for it to be derailed by the conventional wisdom that the early history of life was unknown and evidently unknowable, a view founded on the assumption that the tried and true techniques of the Phanerozoic hunt for large fossils would prove equally rewarding in the Precambrian. Plainly put, this was wrong.
LESSONS FROM THE HUNT
The Gunflint and Bitter Springs articles of 1965 charted a new course, showing for the first time that a search strategy centered on the peculiari-