In a bowl, combine olive oil, oregano, dry basil, garlic, salt and pepper.
Place chicken and shrimp in another bowl; pour over marinade. Cover and refrigerate overnight. Heat about 1 tablespoon marinade in frypan over medium heat. Remove chicken and drain; add to pan and cook until lightly brown.
Remove from pan; set aside. Add sausage to pan; cook over medium heat until well browned.
Add onions and green pepper to pan; raise heat to medium-high; cook until vegetables are soft. Stir in rice; brown slightly.
Add broth, tomatoes, saffron, coriander, chicken and sausage; boil, cover, heat and simmer for 25 minutes, stirring occasionally until rice is tender.
Add peas and scallops; toss gently.
Transfer Paella to large ovenproof 6-quart baking dish or paella pan.
Drain shrimp; push into rice mixture along with clams.
Bake, covered, in 350 degrees oven for 15 to 20 minutes, or until shrimp are pink and clams open.