(soft music) - What does it mean to be curious?

(gasping) For my students, curiosity creates opportunities for a bigger and brighter future.

(air wooshing) (soft music) - The golden wheat fields of the Waterville Plateau in northern Washington.

Just like the plains of West Texas, and yet boulders like these, thousands and thousands of haystack rocks, as they're known locally, are made out of basalt lava.

There has to be a story to these boulders, right?

There is.

It's a 17,000-year old story involving ice.

(upbeat music) (gentle music) So how are you supposed to make a living growing wheat if you have these incredible haystack rocks out in your fields, they're too big to move.

Well, farming has been done here for more than a century around the haystack rocks.

So the boulders haven't been moved by the farmers, but the boulders themselves were moved.

They were carried by the Canadian ice sheet.

17,000 years ago, the ice sheet crossed the border from the north.

The ice sheet was at least 2000 feet thick right here, and these boulders were picked up over by the Columbia River north of here, just a few miles.

And the cliffs of that Columbia gorge were made out of basalt lava rock.

The ice sheet picked up pieces of the basalt, carried them a few miles, and set them here.

It's almost like these haystack rocks have been carefully laid down on a string and plopped right here.

To confirm our story, to make sure it's an ice sheet story and not an ice age flood story, or some other kind of story, let's look carefully underneath Yeager Rock to look for specific evidence.

(soft music) This is Yeager Rock, and this is glacial till, the key to the whole story.

This deposits almost like a nest underneath Yeager rock, and the deposit itself has a sandy matrix to it, this kind of gray stuff.

But there's rocks within this that are kind of polished, angular to sub rounded, most of them are basaltic in nature.

There's no layering, there's no organization to this stuff.

This is poorly sorted rock in glacial till.

If you go to Antarctica today or Greenland today, you'll find glacial till like this being deposited during our lifetime.

So here on the plateau, it's 17,000 year old glacial till.

The ice is gone, but the evidence remains that the ice sheet was right here near Mansfield, Washington.

(soft music) (wind blowing) Hay stack rocks, glacial till, okay, yeah.

But the most famous and beautiful features is also a glacial deposit here on the plateau, the Withrow Moraine, an incredibly delicate, linear ridge composed of glacial till and haystack boulders.

And to the south of the Moraine, there are no boulders.

The ice never got the southern half of the Waterville Plateau, but north of the Moraine, boulders everywhere.

So the Moraine shows us the precise southern margin of the Canadian ice Sheet.

And 17,000 years ago from the Moraine north, 2000, 3000, 4,000 feet of ice.

South of the Moraine, no ice history at all.

The Moraine, the haystack rocks of the Waterville Plateau, a 17,000 year old record of ice in Washington state.

(gentle music) - [Announcer] This series was made possible in part with the generous support of Pacific Science Center.