Season oysters with salt and pepper; dredge in cornmeal.
Heat 1 inch of oil to 350°. Add oysters and cook until golden brown; drain on paper towels.
Cut French bread into 4 sections; slice each section open. Spread mayonnaise on one side and catsup on the other. Place 6 oysters on the 4 bottom slices. Top with lettuce, tomato, and pickle; add top 4 slices of bread. Place on individual serving plates.