Set oven at 375° and butter a 9 x 13-inch baking dish.
To make the biscuit dough, in a large mixing bowl, combine flour, baking powder, and salt. Then stir in milk until just moist. Gently fold in melted butter.
For the filling, combine sliced peaches, raspberries, sugar, and cinnamon. Then empty onto prepared baking dish.
Drop the biscuit dough by spoonfuls evenly over the top of the fruit.
Bake for 40 minutes or until golden brown.