Heat oven to 275 degrees F. Place 1 inch of rock salt in the bottom of a heat proof vessel. (bottom of broiler pan works). Combine bacon, celery leaves, chervil, onions, parsley, and spinach. Sprinkle with the lemon juice. In another bowl combine the bread crumbs, oil and Creole seasoning. Open oysters and discard top shell. Loosen oyster and remove any sand or grit. Push oyster firmly into packed salt. Top each oyster with 1 spoonful of the greens mixture, followed by 1 spoonful of the bread crumb mixture. Press finished oyster into the salt to ensure that oyster remains level. Bake 10-15 minutes.