In a medium-sized bowl, mix together the flour, cornmeal, and oil. Gradually mix in the water and salt. Knead briefly, just until the dough is smooth., Divide the dough into 10 pieces, weighing about 1 3/8 ounces each. Round the pieces into balls, flatten them slightly, and allow them to rest, covered, for at least 30 minutes. This resting period improves the texture of the dough by giving the flour time to absorb the water, and it also gives the gluten time to relax, making the tortillas easier to roll out., Preheat an ungreased cast iron griddle or heavy frying pan over medium heat., Working with one piece of dough at a time (keeping the remaining dough balls covered), roll the balls out until they're about 8" in diameter., Fry the tortillas in the ungreased pan for about 45 seconds on each side, or until they're beginning to brown in spots. (Or, if you have a tortilla baker — use it!), Stack tortillas on top of one another as you remove them from the pan, to keep them soft and pliable. Serve warm or at room temperature., Store tortillas, tightly wrapped, in a plastic bag at room temperature. Freeze for longer storage.