Author
United States. National Park Service
Geological Survey (U.S.)
90
United States. Bureau of Land Management
16
Geological Survey (U.S.),
12
United States. National Aeronautics and Space Administration
12
Billingsley, George H.
10
United States. Forest Service
10
Brock, John C.
9
Kieffer, Susan W.
9
United States. Bureau of Reclamation
9
Pacific Crest Trail Association
6
Priest, Susan S.
6
Felger, Tracey J.
5
Southworth, Scott, 1957-
5
Turner, Kenzie J.
4
U.S. Fish and Wildlife Service
4
BC Parks
3
Cochran, Susan A.
3
Golden Gate National Recreation Area (Agency : U.S.)
3
Horton, J. Wright
3
Parks Canada
3
United States. National Park Service. Denver Service Center
3
Alexander, Terry W.
2
Alpha, Tau Rho
2
Brown, Janet L.
2
Carrara, Paul E.
2
Coastal and Marine Geology Program (Geological Survey)
2
Gibbs, Ann E.
2
Hudson, Mark R.
2
Labay, K.
2
Logan, Joshua B.
2
Madole, Richard F., 1936-
2
Navajo Nation, Arizona, New Mexico & Utah
2
Romig, Joseph Herman, 1872-1951,
2
United States. Bureau of Land Management. Arizona Strip District
2
United States. Forest Service. Rocky Mountain Region
2
United States. National Oceanic and Atmospheric Administration
2
VanSistine, D. Paco,
2
Wahrhaftig, Clyde, 1919-1994,
2
America's Industrial Heritage Project
1
Arkansas. Department of Transportation
1
Barnstable County (Mass.)
1
Beard, Sue
1
Birdseye, C. H. 1878-1941
1
Block, Debra L.
1
Bohannon, Robert G.
1
Bowers, William E. 1927-
1
Brown, G. Allan,
1
Canadian Parks Service
1
Canal Corridor Association (Ill.)
1
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