Ok, same map - now that I've started playing it...I have the map start in 1830. Yet immediately, the map has GeoCore map items on it, and they're as common as anything else is. But shouldn't there be some sort of a "start using this item" date associated with it, since it seems like it would be a pretty late-stage item in the game. By the same token, I have been playing for a while on this map, and ZERO steel mills, dairy production (I have milk production), or canneries have appeared. Meanwhile, my factories are no longer accepting iron (presumably because it would be going to the steel mills), so I have nothing at all to do with my iron sites.
I'm confused as to why this has happened, because they're not disabled anywhere in any of my settings (regional or city).