All along the eastern seaboard of the United States are thousands of oval-shaped depressions.

Some as small as a soccer field, some as large as a small town.

Incredibly, their oblong shapes are mostly all angled the same direction.

They are called Carolina Bays and the explanations for their existence range from the surprising to the astonishing.

The Carolina Bays are up next on Skeptoid.

You're listening to Skeptoid. I'm Brian Dunning from Skeptoid.com.

Decoding the Carolina Bays.

Today we're going to have a look at a minor geological mystery involving thousands of truly perplexing formations,

some science, some pseudoscience, and a lot of genuine curiosity.

We've known about the Carolina Bays for more than a century, and for most of that time we've had no great ideas about how they came to be.

We've had some bad ideas, and some of those still persist today, for reasons that, as we'll find out, are pretty interesting.

The temptation to find an explanation for hundreds of thousands of structures all over the United States Eastern coast is a strong one,

especially when those explanations can also serve to bolster an unrelated theory.

Regardless, today we're going to do our best to find out what we actually do know about the Carolina Bays and how we know it.

If this doesn't sound like a very interesting mystery to you, have a look at the characteristics of the Bays.

The total number of them does indeed range all the way up into the hundreds of thousands, with quite a lot fewer being particularly distinct, numbering probably in the thousands.

At the lowest end, some sources say there are some 900 notable bays that remain pristine and are not impacted by development, most of them in North Carolina.

Obviously there's no firm place to draw the line, so if I said to say there are a lot of them ranging from New York to Florida.

They are depressions, almost as if they were carefully cut into the soil like Gulf Course water traps.

Some are as small as 10 meters across, the biggest measure as much as 5 kilometers.

They have sand berms along the southeast and northeast shores. Most are not filled with water, but some are.

Despite the water, one should not read anything into the name Bay. They are not bays in the conventional sense.

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