The short version The archive turns up 141 records, most of them around Grand Canyon. 2 are confidently dated; the other 139 are educated guesses — about as precise as it sounds. All are free to use.
Sandy bottom creek with winter trees, mid-20th century
1945–1965
Captive Lion, Mid-20th Century Zoo or Menagerie
1940–1970
Azalea Garden in Pine Forest, American South, circa 1940s–1950s
1940–1955
Waterfall in Dense Forest, Kodachrome Slide, circa 1940s-1950s
1940–1955
Mountain Lake with Passenger Liner, circa 1950s
1945–1965
Lava Field with Birch Forest, Northern Landscape, Mid-20th Century
1945–1965
Neoclassical Building Approached Through Overgrown Garden, Mid-20th Century
1945–1965
Will Rogers Shrine of the Sun Dedication or Event, 1940s
1940–1949
Aviario con Flamencos y Garzas, Zoo o Parque Estadounidense, circa 1950s
1948–1962
Desarrollo de viviendas de posguerra en construcción, circa 1950
1948–1956
Autumn Riverbank with Dead Log, ca. 1940s-1950s
1940–1955
Fleet of Orange National Park Tour Buses, Pacific Northwest Mountains, c.1950s
1948–1962
Coastal lagoon with beached boat and mangrove forest, Southeast Asia, circa 1950
1945–1965
Snow-Patched Mountain Range with Forested Valley, circa 1950s
1945–1965
Waterfall in Conifer Forest, Pacific Northwest, circa 1950s
1945–1965
Forest Canyon with Stream, Early Color Photography
1945–1965
Estate Garden with Formal Borders, Mid-20th Century
1945–1975
Institutional flower bed display, mid-20th century
1945–1965
Well Shelter in Rural Orchard, Mid-20th Century
1945–1970
Mangrove Channel, Hand-Tinted Kodachrome, circa 1940s
1945–1955
Mountain Valley Landscape, Mid-20th Century
1940–1970
Tropical River Valley with Dense Jungle Canopy, Southeast Asia, mid-20th century
1945–1970
Desert Wildflowers and Cacti, American Southwest
1940–1949
Alpine Peaks from Aircraft, mid-20th Century
1945–1965
Atoll at Horizon, Pacific, 1940s-1950s
1940–1955
Bat roosting under eave, mid-20th century
1940–1965
Swimmers in Towed Rope Line, Lake or Sound, 1950s
1945–1965
Forest Canopy Study, circa 1950s
1945–1965
Memorial Plaque, Coastal Location, mid-20th century
1940–1970
Wooded Waterside Clearing, Mid-20th Century
1945–1970
Hydroelectric Dam Spillway in Operation, Mid-20th Century
1940–1965
Civic Monument and Domed Building from Riverbank, Mid-20th Century
1945–1965
Chalk Cliff Face with Coastal Vegetation, British Channel Coast
1945–1975
Alpine Avalanche Research Installation, Mid-20th Century
1945–1959
Aerial View of Shallow Reef or Sandbar, Tropical Waters
1940–1970
Aerial View of Volcanic Island with Steam Plumes, Mid-20th Century
1940–1960
Mountain Valley in Mist, Early Color Photography
1940–1960
Desert Wildflower, High Desert Plateau Region
c. 1949
Open-Pit Mine Workings and Waste Dumps, Western North America, 1940s
1940–1949
Arctic Research Station, Boreal Forest in Winter Snow
1945–1965
Mountain Lake at Dusk, Mid-20th Century
1940–1965
Mountain stream in winter, Pacific Northwest evergreen forest
c. 1940
River at Dusk, American South, 1940s–1950s
1940–1955
Rural Landscape at Sunset with Power Lines, circa 1940s
1945–1949
Quarry or Excavation Site with Workers, mid-20th Century
1940–1965
certain
inferred
low confidence