I was gripped, a few years ago, by an article that made the case for the washing machine as the most important invention of the 20th century. Sure, you say, there’s also the refrigerator and the computer and/or the microchip. Penicillin, a discovery rather than an invention, doesn’t count.

The argument has been spelled out in many other newspaper opinion columns, in historical research and even in one of the 20th century’s oddest inventions, TED Talks. Simply put, doing the laundry was once an all day exercise. It was hard, backbreaking labor. It was almost exclusively ‘a woman’s job.’ And when the first powered washing machines came along, they freed up people, almost all of them women, to do other things. Probably it helped with their hand care, too.

I asked my grandmother about this article at some point. She always called it The Wash. If you heard her say it, you heard the capital T and capital W. The Wash. Do you remember, I said, a time before you had a washer and dryer?

“Of course,” she said, in that not-dismissive-but-entirely-obvious way that your elders can use on you.

I asked her when she got her first washer. It was when they’d built and moved into that very house, the only one I’d ever known my grandparents in. It was the 1950s. She was a young woman still starting a new family. The washer and dryer lived on the covered back porch. (Where the laundry connections are is almost a tell. Back porch, that’s hedging your bets on this technology at best, an afterthought at worst. In the two houses I grew up in the connections were in the basement. Out of the way, but inherently inconvenient. In our house today the laundry is upstairs, very near the bedrooms.)

I asked how she did The Wash before she had a washer and dryer. She took it down to the creek. Soap, boards, stones, the old antiquated thing. That’s just what you did. This is the middle of the 20th century.

Which is where my story gets a little foggy. My grandparents’ house was surrounded by a creek. It’s just a small bit of water that breaks off a larger waterway which is itself a slough of a tributary of the Tennessee River — and we talked about that yesterday. If you saw it on a map, my grandparents’ road and the creek almost make a four-way intersection. I started wandering through their woods at a young and early age, when some of those creeks looked like wild, untamable testaments of God and nature. And to my young mind that water was everywhere.

The water was nice. It was always cool, and it always looked clean. But it was never the water that interested me the most, it was the rocks.

Where I grew up was far enough away from my grandparents that the soil was, in places, noticeably different. All of my family lived in this area, a place around a massive river, where the water was a dominant element of everyday life. Having different topographical features where I grew up meant I spent a lot of time playing in the little streams and on the rocky shores.

On a physiographic map this is on something called the Highland Rim, the southernmost section of the Interior Low Plateaus of the Appalachian Highlands Region. By name and almost everything else, it’s a series of contradictions. It’s messy and beautiful.

How the underlying rocks erode in different ways define the area. The rocks formed during the Mississippian period (353 to 323 million ago. Explain that to a kid taken in by the many colors and the smooth polished feel that ages in the water have created.

I lived in a different physiographic region, a bit to the south, in the Valley and Ridge province. Our soil was exclusively clay and, to me, the rocks didn’t have the same sort of interesting character. Has to be that river, I always thought when I was young. I told you yesterday, the river figures into everything, so why not the rocks?

It actually has to do with the mountains.

Kaiser Science tells us:

The mountains of the British Isles and Scandinavia turn out to be made of the same kind of rock, and formed in the same historical era.

Evidence shows that in the past all of these were one mountain system, torn by the moving of the tectonic plates – continental drift.

Put another way, if you like the hypothesis of continental drift, you look at this as a broken mountain range, making these mountains older than the Atlantic Ocean.

A few years ago, longer after the Atlantic Ocean was formed, we visited London and caught a changing of the guard at Buckingham Palace.

There’s a lot of standing around and waiting and jockeying for position and wondering who you’ll see and what the bands will play. It’s good fun if you are patient, and you don’t mind crowds.

We walked to the palace, from wherever we’d been before, through Green Park, and we returned that same way. At one point there in the park I looked down and picked up this rock. It looked familiar. Looked like home.

I brought it back with me, and later took it to my grandmother.

The queen has the same rocks you do!

As ever, my enthusiasm was what amused her most.

If you look at that map, you can see it. The rocks you saw when you were doing chores are the same sort of rocks the queen of the United Kingdom was used to. Their rocks, your rocks, same kinds of rocks.

I wonder when the queen got her first washing machine.