Author
Geological Survey of Pennsylvania
Rogers, Henry D. 1808-1866
3
Pennsylvania. Board of Commissioners for the Second Geological Survey
2
D'Invilliers, E. V. 1857-1928
1
Geological Survey of New Jersey
1
Ingham, William A. 1827-1913
1
Lesley, J. P. 1819-1903
1
Lyman, Benjamin Smith, 1835-1920
1
Pittsburgh Geological Society
1
Shultz, Charles H. 1936-
1
Smith, A. D. W.
1