Coastal plain estuaries: Chesapeake Bay, The sea level rises and fills in the existing river valley.

      Tectonic Estuaries: San Francisco Bay, The land folds or faults and are found along the coast lines



Bar- Built Estuaries: A shallow lagoon or beach is protected from the ocean by sand bars and barrier islands Gulf Coast of North America      



Fjords: U shaped Valleys formed by glaciers found in places like Alaska and northern Europe