The ceiling is called a "techo de bóveda" or arched roof. They're extremely common in this part of Mexico and can be seen in buildings of all types. Practically all buildings except modern high-rises and some warehouses are made of masonry, and they have it down to an art form. Check out the interior of this church in Tapalpa, a little mountain village not too far from Guadalajara. One of my favorite places to get away for a weekend.

EDIT: another shot