Line the dutch oven with heavy duty foil, and to the bottom add the peaches and oranges.
Sprinkle over the top the sugar and cinnamon. Pile the dry yellow cake mix in the middle of the fruit, and make a well on top.
Pour the soda into the middle of the cake mix, and stir themix until it's moist. Spread the cake evenly over the fruit, and top with the cubed butter.
Cook for 45-60 minutes with 8-10 briquettes on bottom, and 14-16 on top.
You can increase the briquettes on top if the cake still looks wet after the 45 minutes. Serve hot with cold ice cream or whip cream, eat up cause it will go fast.