New Orleans File Gumbo

Name: New Orleans File Gumbo
Ingredients: 1 pound Creole or smoked sausage, sliced ½ thick; 1/2 pound lean baked ham, cut into ½ cubes; 1 fryer, cut up; 1/2 pound shrimp, peeled; 1/2 pound white fish fillets; 1/2 cup chopped green pepper; 1/2 cup thinly sliced green scallion; 2 tablespoons finely minced parsley; 1 tablespoon finely minced garlic; 2 cups chopped onion; 1 lg. ham bone, cut into 3 lengths (optional); 2/3 cup vegetable oil; 2/3 cup flour; 2 qt. cold water; 3 1/2 teaspoons salt (less if cooking with ham bone); 1 1/4 teaspoons freshly ground black pepper; 1 teaspoon dried thyme; 3 whole bay leaves; 2 1/2 -3 tbsp. file powder; 1/8 teaspoon cayenne; 1/2 teaspoon dried marjoram