The Ancient Wanderers Among Us

May 3, 2021

Credit NPS

It's hard to estimate, given Covid, but it wouldn't be a risk to guess that, this summer, more than three million visitors to Yellowstone will stop by this park behemoth. It's not as great a favorite as Old Faithful, but the Glacial Boulder, Yellowstone calls it, sits in state like a great gray relic between the trees, as if, like Gulliver, it’s imprisoned by matchsticks. The Glacial Boulder is huge. It shall not be moved, nor has it since it got washed along--that's right, washed along--by an anonymous glacier, impossible as that is to imagine.

Glacial boulders are everywhere really. Yellowstone is full of the big guy's kid cousins. Down the road you'll find a field full, scattered around like a tossed handful of glacial beans. They could be moved, should someone want to rearrange furniture, but no one is going to pick up the mess without a few dozen sticks of dynamite.

Credit Michael Poland

The glacier that left these huge stones is so long gone that its memory is preserved only by all its litter. Glaciers turned out to be lousy citizens, leaving behind a mess as if littering was a joy.

The most celebrated glacial litter in the neighborhood belongs to Cherokee, Iowa, where Pilot Rock, a quartzite monster so huge that once upon a time it pointed clear directions for aboriginals, as well as the white pioneers who wandered out here by way of the Little Sioux River. It's impossible to imagine a 20-foot high, 40-foot wide mountain, 60-feet long--floating along anywhere, but that's what happened. An ocean swept Pilot Rock south and east from its moorings on Gitche Manitou or Pipestone outcroppings--picked it up and quite casually left it behind.

An ocean in northwest Iowa, you say? Hard to believe. I might choose not to if it weren't for Pilot Rock.

Or a less hefty bit of glacial trash, a big fat hunk of granite along the trail to the top of Spirit Mound. There it sits, just off the path, as if someone simply rolled it away, which no one did. It's nothing like Yellowstone's or Cherokee's but it’s just plain weird to stumble on this brute in the middle of tall-grass prairie.

It just shouldn't be there, but go ahead and try to clean it up.
 

Pilot Rock in Cherokee, IA

We've likely all got 'em somewhere, so old a part of the prairie landscape that half the time we don't even notice they're there. No one's ancestry remembers when they weren't here. They’re as ancient as they are huge.

We've got one, sitting on a promontory into the south pond. The conservation board keeps a great trail all the way around the pond, but if you care to get to the water, this huge quartzite sofa is there, although more welcoming than comfy.

You just can't help but love the name, can you?—they’re called "glacial erratics" because they're so much unlike anything else. They're outsiders, outliers. They don't fit in, but they don't seem to be bothered in the least by their own peculiarity. 

They take their name from Latin errara, which means to wander. You may certainly giggle. To call these boulders--even the baby one on Spirit Mound--a "wanderer" is a heckuva stretch because today they shall not be moved.

William Wordsworth, ye old Englishman, was never anywhere close to Siouxland, but that doesn't mean he didn't have something to say about glacial erratics. Listen:

As a huge stone is sometimes seen to lie
Couched on the bald top of an eminence;
Wonder to all who do the same espy,
By what means it could thither come and whence;
So that it seems a thing endued with sense:
Like a Sea-beast crawled forth, that on a shelf
of rock or sand reposeth, there to sun itself.

That's a grand thought. For thousands, even millions of years, the wandering days of these brutes has been over. They're retired. Today, Wordsworth says, they're reposing, catching some rays.

Next time you run through Cherokee, stop by at Pilot Rock. It'll be there. Hasn't much to do anymore, but rest.