To recap what was previously said, abandoned babies could be left at the roda (wheel) of the church. It's somewhat like a Lazy Susan. I took a picture of one in Angra, Terceira, last year when I was there. Others may have different pictures.
The abandoned babies (foundlings; expostos) were assigned to a wet nurse by the camara (town hall). John Raposo wrote an article on this very topic and it can be found in the archives. Many of these babies or children did not survive. The obligation of the family was to feed and take care of their own children first. If the exposto lived to the age of 7, he/she could chose to stay with that family or could chose to go his own way.
For those who think the roda scenario is kinda of strange: In my area of southern California (although I believe this is a statewide thing), an unwanted baby can be left at a fire station or at a hospital. The mother will not be charged with any crime if she leaves her baby at one of these places.
Cheri