clovis,
If it really has no bark then difficult to id is an understatment.
When i look at the outside of the picture i see bark of what looks like white walnut, but this could be just underbark of something that has fallen off long enough for likens to grow on the outer wood.
As for softwood having thicker growth rings, yes in general but not always.
What was the smell of this piece of wood when you cut it?