Grover, Nathan Clifford (1868-1956) Lamb, William Alfred (1881- ) Paulsen, Carl G. Follansbee, Robert (1879-1952) Spiegel, Jacob Birk Kinnison, Harvey Banks (1890- ) Beckman, Henry Claus (1888- ) Stany Zjednoczone. Geological Survey

Grover, Nathan Clifford (1868-1956) Purton, Astley B. (1886-1962) McGlashan, Harry Deyoe (1879- ) Henshaw, Fred Forbes (1884-1933) Paulsen, Carl G. Follansbee, Robert (1879-1952) Stany Zjednoczone. Geological Survey

Grover, Nathan Clifford (1868-1956) Baldwin, George Clyde (1884-1951) Parker, Glenn Lane (1884-1946) Paulsen, Carl G. Purton, Astley B. (1886-1962) Henshaw, Fred Forbes (1884-1933) Stany Zjednoczone. Geological Survey