Thorium and rare earths in the United States, exclusive of Alaska and Hawaii

The accompanying map shows the location of the principal deposits of thorium and rare-earth minerals in the United States (excluding Alaska and Hawaii). Symbols of different shapes are used to depict deposits of different geologic types, and sizes of symbols denote the relative importance of the deposits. Because of scale limitations a symbol may represent groups of deposits too closely spaced to permit them to be distinguished separately. Some districts of considerable extent arc shown by a shaded pattern.