I have been given some nice big lumps of this. Lots of big splits and spider nests but I should be able to find some decent pieces in the bits in between. I chiselled off a bit - redder underneath - oak maybe?
Definitely is oak. I cut it all up with the chainsaw and managed to get some decent lumps without too many splits. Today I made the big lump at bottom left of the photo into a lidded box. My arms and face were black from the tannins.