Why can't I build a quarry on the Kaolin?

[Markus5]

The kaolin on the left has a quarry. I can't build a quarry on the right one. Its in the city limits. Ideas?

 

[disjointaccount]

Until whatever you're constructing on that tile above the city centre is finished, you don't actually have anything connecting you to the kaolin tile

 

[Markus5]

Really. Of course.
<duh>
It's obvious now.
</duh>