Heat oven to 350°F. Grease 13x9-inch pan. Lightly spoon flour into measuring cup; level off. In large bowl, combine flour, sugar, baking powder, salt and orange peel. Using fork or pastry blender, cut in margarine until crumbly. Add milk, vanilla and eggs; stir until well blended. Pour 3/4 of batter(2 1/4 cups) into greased pan. Top with peaches and blueberries. Spoon remaining batter over fruit.