Once upon a time, before Idaho disappeared, the land that came to be known as "Idaho" was flat as Kansas or Saska...Saksa...the province to the right of Alberta as you face North. It was, geology has shown, a high, flat, plain and rather boring from end to end.

Then came the potato.

What is known to only a few -- it's kept secret by the US Dept. of Agriculture and you'll learn why in just a minute -- is that potatoes are not vegetables!! Potatoes are actually a sightless, subterranean parasite much like a nemotode. Potatoes take their nutrients from the roots of what we call the "potato plant" or "potato vine". Potatoes will travel many miles (or kilometers in Canada or England or Ireland) to latch onto the roots of this plant, much like leeches do to warm-blooded creatures. The potato will suck the life from the plant if permitted to do so.

Potatoes were indigenous through the Idaho Plateau. There were literally millions of the critters, and when humans began planting potato plants the potatoes were of course attracted to their primary food source.

But humans didn't plant the potato plants evenly. No, they concentrated them in farms, in areas convenient to the humans. Thus the potatoes, generation after generation, migrated to what was, to them, a cheap and easy food source. But when the potatoes migrated nothing moved in behind them to fill the underground space that was vacated. Gradually, the land caved in, filling in the areas once full of potatoes. In many areas of Idaho this migration was so great, the swarms of potatoes so huge, that eventually the rocky "spines" underground were all that was left, and humans coming later thought that Idaho had always been covered with mountains.

This is a simple explanation, of course. You can read the entire story in Larribee's definitive work, Idaho Geology: The Challenge of the Potato (Moscow, Idaho: University of Idaho Press, 1947). Of course, the U of I no longer exists but you might find the book in some library somewhere.