Occasional blog and online home of Paul Wallace

  • Local Pages

  • Quote of the month

    And I was some of the mud that got to sit up and look around. Lucky me, lucky mud.

    -- Kurt Vonnegut, Cat's Cradle

  • Facebook

    The surprising joys of the late Precambrian

    Beauty etched in stone: A fossil of Spriggina floundensi, discovered in the Flinders Range of South Australia. This animal, which may have been a precursor to the trilobites, lived during the Ediacaran Period, the last of the Precambrian Eon. The fossil shown is about 3 cm long. Image source: Wikimedia Commons

    In today’s New York Times there is a wonderful article about life in the Precambrian and the scientists who are uncovering it. This long-mysterious period, which began 4.5 billion years ago — at the Earth’s very assembly — and ended about 500 million years ago, has given up a number of its secrets in the last 50 years. Accompanying the article is a beautiful slideshow which opens with these words:

    In Charles Darwin‘s day (and for many years after), no fossils were known in the enormous, older rock formations below those of the Cambrian. This was an extremely unsettling fact for his theory of evolution because complex animals should have been preceded in the fossil record by simpler forms.

    It took a very long time, and the searching of some of the most remote places on the planet — in the Australian Outback, the Namibian desert, the shores of Newfoundland and far northern Russia — but we now have fossil records from the time immediately preceding the Cambrian. The rocks reveal a world whose oceans were teeming with a variety of life forms, including primitive animals, which is certainly good news for Darwin.

    Amazing. These are animals that swam and crawled over 500 million years ago. Half a billion years. What a world this is! I must admit: When I see images like this and contemplate what has come before, I almost begin to weep. I’m not sure why, but thinking on such things fills me with a strange combination of peace and awe that I can only describe as religious.

    Yes, it’s true: Meditating on tiny segmented animals moving along the sea floor half a billion years ago makes me feel, in the words of Meister Eckhart, empty and free. Why is this, when knowledge of such time scales and the thoughts of repeated worldwide mass extinctions should make me worry about basic Christian notions like a loving creator God? Why so many sloppy starts and restarts? Why so much trial and error? Why so many obsolete species? Couldn’t God do better? With an efficiency proper to God’s omniscience and omnipotence? Yes, I should wonder about these things, but I don’t. I just can’t bring myself to get too concerned. Instead, dwelling long on natural history often moves me to joyful tears and even leads me to whisper a spontaneous prayer: Thank you.

    This, to me, is a curious fact.

    I have written elsewhere of my early introduction to the geologic timeline. My dad showed it to me one day in our wood-paneled den in the late 1970s. It was in a Time-Life book on natural history. I looked and stared, stupified. With its boxes and numbers and colors and fine print the timeline seemed to me a thing of great elegance. The words — Ordovician, Silurian, Jurassic, Eocene — were themselves rare discoveries, whatever they signified. Standing at the edge of that precipice thrilled me. It got me to thinking and imagining. Later I asked Dad how we knew about life’s history. With the enviable ease of one who knows he answered, careful observation. Fossils. Radiometric dating. Not once in my life have I doubted any of it. Not that I understood, but answers are more than words. His eyes shone and there was no turbulence in his voice. Knowing is such great pleasure.

    I had thought a lot about dinosaurs before this. For a year or so around first grade they had been just as real to me as my own family. My large collection of plastic dinosaurs was fully accessorized with volcanoes, era-appropriate flora, caves, cavemen. (The latter were not at all era-appropriate, it turned out, but they surely added to the drama.) At the far corner of the playground at school there was an outcrop of rock that looked pretty prehistoric to me. Mornings I slipped a few Tyrannosaurs and Stegosaurs into my pockets and during recess lost myself in dreams of the Mesozoic. The marvelous beasts swam and flitted and lurched and died in my imagination. I could smell their acrid breath and hear their creaking joints as they lumbered by. But until Dad shared the timeline with me, I had only known that before there were people there had been dinosaurs. I had never properly stood face-to-face with deep time. I found mystery in it, and comfort somehow. Evenings I lay in bed and read the Time-Life books, and, in wonderment at the miracle of life, pressed the structure of the past into the soft clay of my young mind. Eventually I wearied and dropped down that great well of natural history into sleep.


    Latest posts