Those pillars are about nine feet high and eight feet apart.

On the top of each pillar is first of all a thick block of stone projecting about eighteen inches from the pillar on its upper and lower sides.

Then on this was a rather thicker block of stone, and on the top of all cross beams of solid single stones had been laid, and from one cross beam to another were solid and closely put together slabs of stones, some of which were eighteen inches wide, and some rather wider, thus making a roadway above so narrow that two carriages cannot pass each other.

In order to strengthen the pillars and keep them in position, a flat slab of stone had been laid on the bed of the river, from the base of the lower pillar to within about two feet of the upper one, and between the end of this slab and the pillar a thick, high block of stone had been wedged.

In this bridge there were 109 pairs of pillars, giving a total length of about 1,000 feet.