Thaw scallops, if frozen. Chop shucked clams, reserving juice; set clams aside. Strain clam juice to remove bits of shell. (Or, drain canned clams, reserving juice.) If necessary, add water to clam juice to equal 1 cup. Set clam juice mixture aside.
In a large saucepan or Dutch oven cook bacon until crisp. Remove bacon, reserving 1 tablespoon drippings, if desired. Drain bacon on paper towels; crumble. Set bacon aside.
In the same saucepan combine reserved bacon drippings (if desired), reserved clam juice mixture, potatoes, shallots or onion, dill, bouillon granules, and pepper. Bring to boiling. Reduce heat and simmer, covered, about 10 minutes or until potatoes are tender. With the back of a fork, mash potatoes slightly against the side of the pan.
Combine milk, half-and-half or light cream, and flour until smooth. Add to potato mixture along with shredded carrot. Cook and stir until slightly thickened and bubbly. Stir in clams and scallops. Return to boiling. Reduce heat; cook, uncovered, for 1 to 2 minutes more or until clams curl around the edges and scallops are opaque. Stir in sherry.
Sprinkle each serving with crumbled bacon and, if desired, garnish with additional dill. Makes 4 servings.