Melt butter in a 2 1/2-quart baking dish.
Combine flour, 3/4 cup sugar, and baking powder; add milk, and stir until blended.
Spoon batter over butter in baking dish; do not stir.
Combine peaches, blueberries, and 1/2 cup sugar; spoon over batter.
Do not stir.
Bake at 350Â° for 45 to 55 minutes.