In a small saucepan, stir together 1/2 cup of sugar, cornstarch and orange juice. Cook until bubbly, add peaches and blueberries, cook until hot. Keep warm. Stir together flours and baking powder, add milk and oil and stir until mixture forms a ball. On floured surface, pat into an 8 inch circle. Cut into wedges. Spoon hot berry mixture into 9 inch pie plate and top immediately with pastry wedges. Sprinkle with sugar. Bake in 425ºF.  oven for 20 - 30 minutes or until pastry is browned. This cobbler has a grandmother flair! Serves 8