I had only two marshes for four continental cities.
Apologies for the false pregnancy report: the tech tree threw me off. Under Guilds it replaces "windmill" with an icon that translates to "construct a polder." I assumed that the windmill replacement was called that, as opposed to a terrain improvement that, for all I know has nothing to do with the windmill, but with guilds.
With regard to the thread itself, I also thought it's become too unwieldy. Would it make sense to have a reserved space up front where one post lists everything confirmed below?