A high level view of the southern outer apse.
The top left corner of the porthole doorway
to the inner southern apse can just be glimpsed above the upright
slab mid-right. Note the exact fitting of the horizontal courses into the top of
the upright slabs in the apse wall, centre.
The "snake veined" threshold slab is visible far left as is the
"libation hole" in the threshold stone of the inter-apse
portal far right.