Say, a 1910 lobby, all full of fruity-looking marble, in the best spec builder style.

 

 

The big marble panels, say, 2 or 3 by 4 or 5, how are they affixed, if all all.   Yes, gravity does the work.   But is there any bubble gum between them and the common brick backing?    Some kind of anchor?   Luck?

 

Sincerely,

 

Oxygen