WTF is this on my block? (pics)

Well, it's time to get this car together. The engine (D15B7) had 243,300 miles on it when I got the car, and wasn't running. Rather than just fix whatever was wrong and hope nothing else happened soon, I decided to tear the whole engine apart and give it a nice refresher, new gaskets, rings, bearings, hoses, etc.

While cleaning the block (and this thing was FILTHY), I came across this little gap or whatever it is on the outside front of the block.
http://img.photobucket.com/albums/v695/sideshowrich/DSC00767.jpg
http://img.photobucket.com/albums/v695/sideshowrich/DSC00766.jpg

It's not big, maybe 1mm at its biggest. I've shot steam at it from different angles, and nothing comes out of any oil or coolant passages. Is there anything on the inside this part of the block, such as an oil or coolant passage that might be clogged, or is this just some imperfection that is harmless? I want to get this mystery solved before I start buying parts for a possibly dead block.

thats crazy lookin maybe it had a crack in it and some1 tig welded it back up.

I don't see and evidence of it being welded, it almost looks like it's a chip on the surface. I'd just hate to waste $$$ getting the engine back together only to find out that the block is screwed.

Anyone else?

looks fine to me.

looks fine to me.
agreed

agreed
I concur.

Looks fine to me to.. That is nothing more than a small blemish/flaw made during the casting process.

Well, good, this makes me feel a lot better about it. I hope to get this thing back together before the summer, but I still have a ways to go.