In this picture, we see the front (Jerusalem) side of the synagogue. The basalt walls in the upper portion of the image is where there was a platform on which stood a wooden box ("ark") in which the synagogue scrolls were stored. There may also have been a genizah (a place where worn-out scrolls were deposited) in this area. Note also the square room in the upper left of the image.
The Mosaic is very interesting! In the center is a Torah Shrine ("ark") that has wooden doors and a curtain that is tied. Two columns, with Ionic capitals, support a gable roof with a shell in the center of it. It looks like three stairs lead up to this shrine—there may have been three wood stairs leading up to the actual "ark" on the black basalt platform.
On each side of the "ark" is a menorah, seven-branched candelabra, on a tripod on a stand, and "flames" in the seven bowls. At the base of each menorah is a lulav (palm branch associated with the festival of Succoth) and a citron (etrog) along with an incense shovel and a ram's horn (shophar). All of these articles are associated with worship in the Jerusalem Temple—which had been destroyed in AD 70.
Several bands of various colors and a guilloche form the border of this portion of the mosaic "carpet."
This synagogue dates to the 4th-5th centuries.