My clay?

I wonder if the clay under my flood plain is similar? It appears to be of volcanic origin laid down several glacial period in the past.

At least the mason bees love it for capping their nests.

It probably is very similar. I do not know what it would take to get it tested for content - especially toxic junk.

The power of the clay to absorb might be the issue if the source is in the flood plain. The flood plain is picking up all the toxins from up stream and the clay is absorbing them.

But if there is beneficial clay in your area, then I think you could probably find some healthy veins on your property.

This might be a good place to start - http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm