Lancaster Mediaeval Bridge Foundations

Took this composite photograph of the underwater remains of the Mediaeval Bridge a few years back. The tide was out and the Lune was very clear.
This is the side closest to Skerton. I still don't understand what the track-like features actually are.
Nearby Photos
Nearby Dive Sites
Capernwray Quarry 11 km
Devil's Bridge 21 km
Bailif Wood 36 km
Eccleston Delph Quarry 47 km
Wast Water 53 km