The blue banner at the top of the production screen is called the warehouse. It lists all the resources and commodities your nation has this turn. 

If you are not sure which resource or material an icon represents, place the mouse over the icon and read the text on the gold banner in the upper right portion of the screen.

When you end your turn, resources you have connected to your capital city on the map are moved into the warehouse for use on the next turn. Materials you make on this screen are added to the warehouse for next turn as well.