The description of wind-tossed South Dakota prairie grass as an ocean is nothing new, certainly, but it is enduring.

My mom sometimes would say the brome grass blowing in a northwest breeze in the field near our mailbox reminded her of waves on the ocean. She had seen an ocean, too, the Pacific, on one of our madcap vacation trips. The water reaching out to the horizon, and the way the waves broke on the Oregon shore and swept across the sand, fascinated my mother. They frightened her, too, which the tall, familiar, breeze-blown grass she had known all of her life in Lyman County never did.

I used to remember my mother’s description when I’d interview older South Dakotans about their first days on this land. At some point in the conversation — and I tried to treat such interviews as conversations, to keep the memories flowing easily — most of the oldest of my interview subjects would mention the vast stretches of waving grass they had seen before plows broke the sod and turned so much of that grassland into fields. And most of them, at some point, would talk about a “sea of grass’’ or a “green ocean.’’

I had the good fortune once to sit at the kitchen table of an old woman in the south central part of the state and listen to her story of arriving at that spot from back East somewhere as a young woman. She had traveled by train and was sleeping when the rail cars stopped rolling. She awoke just after daybreak, she said. When she raised the window shade and looked out, she couldn’t believe what she saw. “Grass, grass and more grass,’’ I believe is the way she described it, “farther than I could see.’’ And, she added, she felt as if she were adrift in an ocean.

I also recall an interview perhaps 30 years ago with a Perkins County woman who was fast approaching the end of her first century on the planet. She came to the Grand River Valley as a young girl, bouncing with other members of her family in a covered wagon northward through what she described as some of the tallest, thickest grass she’d ever seen.

The early settlers sometimes described those covered wagons as “prairie schooners,’’ apparently because, lost in a sea of billowing native grasses, they resembled an actual sailing ship called a schooner as they bucked and plunged through the unbroken grassland.

The old woman said it was easy to ride along in the wagon and feel as if it was a ship on the ocean. Like the woman from south central South Dakota, she said the grass stretched and stretched until it disappeared somewhere beyond the horizon.

Well, the plows and the livestock herds, along with the railroads, highways and towns, have eliminated much of the native grasses in South Dakota and across the rest of the region. It’s still possible, though, to find places where a solitary traveler with an active imagination could feel as if he had slipped back a century to the time of those oceans of grass.

I did just that the other day on a trip home from business in Murdo. I went down Highway 83 and out on the interstate going to the meeting, but I took the back road, old Highway 16, home. The 20 or so miles from Murdo to the 83 junction are posted 55 mph, and I stayed pretty close to that speed. I mean, 20 miles? The difference between 55 and 65 is what, a minute? Two minutes? And the condition of the highway favors the slower driver. So I had a leisurely trip over the two-lane road, and with almost no other traffic, I enjoyed the scenery.

There were stretches where tall grasses grew on both sides of the highway off over the first hills. The wind blew about 15 mph across the roadway, and the grass bent and lifted and flung itself around as if alive. Rippling under the sun, the grass appeared alternately flaxen and purple. It wasn’t like the days of the settlers, but it was close enough for one afternoon.