Buildings

The buildings within the hospital site where I work are many and varied, having been built at different times over the last 200 years.  
The building pictured fascinates me as it has a number of strange "additions" on the roof.  One looks like a turret, and there are a couple of these round stone structures.  I am told that they are chimney stacks, but I'm not convinced - a bit more research needed I think!