In a large bowl, stir together the flour, sugar, bicarb soda, salt, nutmeg and cinnamon. Cut in the margarine until the mixture appears mealy. Stir in the egg, mashed banana and oatmeal until well blended. Drop by rounded spoonfuls onto an unprepared baking tray.
Bake for 8 to 10 minutes in the preheated oven. Remove from baking tray to cool on wire racks.