An iced drink made with a little sugar dissolved in wine or liqueur, with lots of ice, topped with fresh berries and served with a short straw--the straw being a critical component since it was a fairly new invention that kept poor teeth a safe distance from the ice, which wasn't generally available before either.
From Jerry Thomas (1862)
"Like the julep, this delicious potation is an American invention, although it is now a favorite in all warm climates. The "cobbler" does not require much skill in compounding, but to make it acceptable to the eye, as well as to the palate, it is necessary to display some taste in ornamenting the glass after the beverage is made. We give an illustration showing how a cobbler should look when made to suit an epicure."