Come on, there is way too much superstition being thrown about in this thread.
The bible does not ever place any particular damnation on someone who digs up a burial site, either on purpose or accidently. and for that matter there is no special prayer that needs to be said either. And I cant say i blame maverick, 20 years later and 2000 miles away, I sure wouldnt go back either.
If you find out that this stuff is part of the cemetary, then I am sure the city will let you put it back.
If not then throw it away lol. And by the way, now that someone mentioned the drainspout, I think I would have to agree with that. I was just checking out a very old building today for a new metal detecting spot while it was raining, so I noticed the drainspouts. They look very similar to what you have, a bit different from modern ones. I seriously doubt those are anything to do at all with a cemetary. No offense is meant by what I said, but superstion will only make people live a fearful existance, and i just wanted to clarify that biblically nothing is put forth on this subject, and so you do not need to have any extra worries about that.