Wash trout briefly under cold, running water. Pat dry inside and out with paper towels. Sprinkle cavities and skins with salt and pepper. Mix cornmeal and flour. In heavy 12-inch skillet, melt the butter with the oil over moderate heat. When the foam begins to subside, roll each trout in the cornmeal-flour mixture, shake off excess, and place trout in skillet. Fry 4 to 5 minutes on each side, until golden brown and crisp and flakey when probed with a fork. Serve with lemon wedges. Serves 4