DeletedUser32426
Sorry, for taking so long a time to reply. My age of the city is Colonial. I do have the Lighthouse but not the St Marks GB.Do you have a Lighthouse of Alexandria or a St Marks Great Building? These buildings boost the amount of supplies and coins you can generate in your city (so you can possibly have less supply making and coin producing buildings. It will depend on your goals and the design of your city).
What age is your city?