"Vistula Bay" is not idiomatic English. It should be "Vistula Lagoon". cf. http://www.britannica.com/eb/article?eu=77522 In the same way, "Vistula Peninsula" should be changed to "Vistula Spit". (cf. same link)
"Vistula Bay" and "Peninsula" are valid descriptions, but not their geographic names in the English language.