Wagon With Aron?

The image below is taken from an ancient synagogue (built around the fourth or fifth century) in Kfar Nachum, Israel.

If you look closely, the picture below seems to show a wagon with a box (ארון?) on it.

What do you think this picture was meant to depict? Do you see anything else in this image?

Below is another image of the ruins of the synagogue.

An ox attached to a wagon..