Stir together flours, salt, and yeast in a medium bowl. Add water and olives, and mix well using a wooden spoon or your hand until dough is wet and sticky.
Cover with plastic wrap; let stand at room temperature until dough doubles in volume and the surface is dotted with bubbles (approximately 12-18 hours).
Transfer dough to a floured surface using a rubber spatula or a bowl scraper to scrape dough from bowl.
Fold dough using lightly floured hands, lifting edges toward the center. Shape dough into a loose round.
Generously dust a clean kitchen towel with wheat bran, cornmeal, or flour (I used cornmeal). Gently place dough on towel, seam side down. Dust the top lightly with wheat bran, cornmeal, or flour.
Loosely fold ends of towel over dough to cover. Let stand in a warm place until almost doubled in volume, 1-2 hours (the dough should not spring back when pressed).
After dough has risen for 30 minutes, preheat oven to 475 with rack in lower third of oven.
Heat a covered 3 1/2 quart heavy ovenproof Dutch oven (9 inches in diameter) for 30 minutes or until dough is ready.
Carefully remove preheated pot from oven, and uncover. Unfold towel, and quickly but carefully invert dough into pot, seam side up.
Cover with lid. Bake for 30 minutes.
Uncover pot, and bake until bread is dark brown (mine was golden brown)but not burned, 15-20 minutes.
Carefully lift bread from pot using metal spatulas, and transfer to a wire rack to cool completely.