Author
Geological Survey (U.S.)
50
Bromery, Randolph W. 1926-2013
49
Zandle, Gerald L.
43
Henderson, John R.
8
Bennett, Bruce L. 1917-2003
4
Petty, A. J.
2
Andreasen, Gordon E., 1924-
1
Gilbert, Francis P.
1
Griscom, Andrew
1
Johnson, Robert W., Jr., 1924-
1
McIntosh, F. K.
1
Mosier, McHenry
1
Natoff, Nora C.
1
Pennsylvania. Bureau of Topographic and Geologic Survey
1
Pennsylvania. Department of Internal Affairs
1
Popenoe, Peter
1
Tyson, Natalie S.
1