The Apse Mosaic at San Clemente: Detail, Jerusalem

The rump of the rightmost of the sheep can be just seen on the left.  Above it is the inscription "Hierusalem." The cross above the gate corresponds to the child above the Bethlehem gate on the far left: Jerusalem was the city where Jesus died, as Bethlehem was his birthplace.

View the entire apse.

Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.