An exciting discovery today -- a very well-made flagstone floor. We started the day in locus 12, taking it down to the level of the closing elevation of locus 07. We have two courses of massive boulders along the north wall of the passageway and three courses of smaller stones comprising the west side of the passageway. An incomplete obsidian blade was found in locus 12, toward the bottom (it was taken out of the nasilki, so I could not point provenience). In the afternoon, I resumed in locus 11, just evening out the locus. In so doing, while trowling in the west corner of this locus I came upon the start of the flagstone floor. I created a new locus, 13, to follow the westward continuation of this floor. Locus 13 is a long and narrow locus that runs parallel to the interior line of stones. Thus far, the stone floor continues along the entire excavated length of locus 13. Will take macrobot samples from above the flagstone floor tomorrow (the areas of it not yet excavated).