This text states that although all estuaries are similar in that they are semi-enclosed bodies of brackish water, they are categorized with regard to geological characteristics, and further distinguished on the basis of stratification and circulation patterns. According to their geological characteristics, estuaries are classified as: drowned river valleys or coastal-plain estuaries, bar-built estuaries or lagoons, fjord-type estuaries, and tectonically caused estuaries. Each type is explained in detail and examples are given for each. Educational levels: High school, Middle school
