Charcoal in my soil

We moved here 3 years ago and the 20x30 garden was in place, this year as I was transplanting my tomatoes, using a post hold digger to get them deep into the ground, I found charcoal bits about 2 feet down.
I've read they are good for the soil but am surprised they are so far down.
The first one foot of soil is dark , (in the back ground) below the soil is red clay but has these charcoal bits, (marked with the white stake) I'm happy but don't understand why they are so far down ? Can not find any in the upper level ? Dwight
Pic next post

This message was edited May 23, 2010 9:59 AM

Here's the pic

Maybe a wooden structure burned down on that spot a long time ago?

Maybe so

That;s interesting. An archaeologist could probably guess. But a structure, or an old fireplace from native people? I wonder how long it takes for a foot of new soil to form on top of that.

I have been working my garden since May and have found it through the soil, not just 2' down.
Have read about the Amazon gardeners using charcoal to enrich their soil, many years ago.
Charcoal holds nutrients that can be used over a long time.
Today it's called biochar....check it out here on DG and the net.
It was just another plus I received when we bought this home.

Dwight