1In a large bowl, mix the flour, oats, salt, and soda. Make a well in the center; add enough buttermilk to make soft dough. Form in a ball. On a greased baking sheet with floured hands, flatten dough into circle 1 ½ to 2 inches high. With floured knife cut cross 3 /4 inch deep in center. Bake in a preheated 425 degree oven for 25 minutes; reduce heat to 350 and then bake for an additional 15 minutes. Let cool on rack at least 5 hours to allow bread to set. Note: If crust seems too hard, wrap bread in damp cloth while it cools.