This is the corner block wall foundation for an attached garage. The garage floor is a poured slab. Gutter looks like it has been pouring water in that area for some time. It looks like there may be some displacement.
The second set of pictures (next post) is what looks like to be a separate foundation for the fireplace (directly above these blocks). The only thing is they did not take the block all the way to the joists. It looks like they just shimmed it up with what ever they had laying around.