This is a bit of concept art for my FM. It's a picture of the Shale Bridge. It's based on the old London Bridge and other similar examples.
I have speculated that this bridge was built upon the original crossing point of the river. Settlements were often formed around such natural fords, and we have speculated that "shale" may have evolved from shallow (and this ties in neatly with the servants conversation).
We are now working with the idea that the area of Shalebridge takes in the bridge itself and also surrounding streets on both sides of the river. (It may well be there is no real life example of a district straddling a river like this; personally I don't care, this is a fantasy setting after all, and it's a good idea). We have also stressed that it is not an official district or quarter, but rather something that has come into common usage by the inhabitants of the City. The only question that remains is how far this area extends into Old Quarter and Dayport. So far, I think Doc_Brown hit the nail on the head in his last post. Remember though, that an un-official area you might get different opinions depending on who you talked to in the City; in short there would be a bit of a grey area, so it might be acceptable, even preferable, to be in-precise about this.