About a decade ago I was cruising up a 130-mile long reservoir behind America’s largest dam – Grand Coulee – built across the mighty Columbia River. The area around the reservoir is rural, but it’s hardly the isolated wilderness of the Yukon. Nevertheless, geologists are still finding some quite intriguing things that lie in such rural places, because there are many outcrops still on Earth that we just haven’t looked at seriously.
What had drawn me to the reservoir was evidence of Ice Age catastrophic flooding that raced across the Northwest from Montana. The evidence for that story is abundant, with legions of outcrops telling the tale. Typically, of course, we geologists drive to those outcrops in pickup trucks – it’s part of our culture to drive everywhere in trucks (the larger, the better, at last until quite recently).
But on the particular summer’s afternoon I have in mind, I had left the world of pickups behind. The shores of Lake Roosevelt – for many miles – are steep bluffs. There are no roads above or below the bluffs. There are no trails, even, that could let you hike from the top of the bluffs to the bottoms.
So I was in a motorboat.
I had borrowed the boat from family friends – only great kindness, I suspect, allowed them to lend it to a novice boater like me. But I managed to tow the craft to the reservoir, get it in the water, and start the motor. And one fine afternoon, I cruised into an inlet and saw a big waveform embedded in the sands of the solid bluff. Because of my location that day above the confluence of certain rivers, I knew it was evidence of a catastrophic flood coming down from Canada to the north – not from Montana to the east. Viola! One wholly new suggestion to make to my colleagues about Ice Age history here in the Northwest.
One hundred years ago this summer a much bigger geological find was made by a prominent American paleontologist. Charles Walcott was looking for fossils from the specific time when animals in the sea first became large and complex. Earlier in Earth history, life in the seas had been very simple – not much more than worms and very elementary jellyfish – but all that changed in what geologists call the Cambrian Period. Near the start of the Cambrian, quite suddenly, sea creatures appear in the fossil record that were much larger, had shells and even had eyes.
Walcott had spent the summer of 1909 in the Rockies of British Columbia, hiking to look for fossils in shale of Cambrian age. One late summer’s day he hiked up to a particular high-elevation ridge – and there at his feet were pieces of shale with a cornucopia of fossils that we geologists are still studying.
Walcott’s rocks are part of the Burgess Shale, and they’ve taught us how varied early life was in the Cambrian. Some Burgess animals had five eyes, others had complex pincers out their snouts. Some of the animals are so odd they seem like hallucinations – one has even been named “Hallucigenia” in honor of that idea. But, of course, each of the strange fossils were once real, flesh-and-blood animals in the Cambrian seas.
We don’t know why the five-eyed animals went extinct and animals more similar to our basic body planned survived. Likely, there was a good factor of chance involved, and it could have come out quite differently. But one thing is certain, it was us two-eyed creatures that lived and became the animals that appear in all subsequent geologic periods.
Walcott’s hike 100 years ago helped to propel the science of paleontology forward. It has taught us that animal life on Earth likely could have played out in many of variously different directions.
Here’s wishing you a dozen more summer-evening strolls before autumn starts September 22nd. Keep your eyes open for gems of all kinds, because you may be the first person at a particular spot to look for what will literally be laying at your feet.