Szczecin Lagoon Szczecin Lagoon Szczecin Lagoon, Stettin Lagoon, Bay of Szczecin, or Stettin Bay (, ), also Oder lagoon (), is a lagoon in the Oder estuary, shared by Germany and Poland. It is separated from the Pomeranian Bay of the Baltic Sea by the islands of Usedom and Wolin. The lagoon is subdivided into the "Kleines Haff" (, "small lagoon") in the West and the "Wielki Zalew" (, "great lagoon") in the East. An ambiguous historical German name was "Frisches Haff", which later exclusively referred to the Vistula Lagoon. From the South, the lagoon is fed by several arms of the
Freshwater Lagoon the Mad River estuarine wetlands 30 miles (50 kilometers) to the south. Freshwater Lagoon is similar to other coastal features of northern California including Humboldt Bay to the south and Lake Earl to the north. An alluvial plain is surrounded by steep uplands. Hills adjacent to Freshwater Lagoon have been identified as undivided pre-Cretaceous metasedimentary rock. Studies around Humboldt Bay indicate tectonic activity along the Cascadia subduction zone has caused local sea level changes at intervals of several centuries. The plain may support fresh water wetlands or Sitka Spruce forests following uplift events and salt marsh or inundated shellfish beds