Primitive Technology

I'm not sure if this is the right sub to ask this in. I also posted this in r/clay, but here goes:

Three days ago I dug up my own clay. It comes from a moat that was cleared by a digging machine and a whole lot of it was sitting right there. It looked nearly pure and I only had to wash out minor debris.

After washing and pouring everything through a sieve I was left with a sludge mixture the consistency of paint. It's now been three days waiting for it to settle to the bottom but it seems to just have stalled. Touching it slightly it's still way too watery for me to pour it off.

Is this normal and should I just wait much longer? Most tutorials online don't tell me what is happening. When I grabbed it from the side of the road it was elastic and smooth. I also really couldn't tell you what kind of clay it is. It's a very dark grey.

Any help is appreciated!