I'm in the process of digging holes for concrete piers (for a small deck - nothing fancy) and on my last hole I came across what appears to be an underground railroad tie (or some other huge piece of wood with a sticky tar on it).
Here's a picture:
I tried to just avoid the wood by moving the hole down a bit but then it becomes misaligned with the rest of the holes (which in turn messes up my plans for the deck foundation).
I don't relish the idea of having to re-dig 8 other holes just to workaround this. Is there an easy way to cut into this piece of wood? It's not associated with any large structure so cutting a piece out of it won't cause any structural issues in the surrounding area.
I tried using a simple chisel and that yielded little results. I'm thinking perhaps a sawzall? Or chainsaw? Cutting in vertical lines... then chiseling that off?