The short version The archive turns up 107 records, most of them around Grand Canyon. 2 are confidently dated; the other 105 are educated guesses — about as precise as it sounds. All are free to use.
Aspen and Conifer Forest, Grand Canyon Rim, 1948 1948 · Grand Canyon Grand Canyon Erosion Study, 1944 1944 · Grand Canyon Water Skiing, Inland Lake, circa 1950s 1945–1960 Dahlias Behind Chain-Link Fence, 1950s 1945–1960 Niagara Falls from the Canadian Shore, 1940s–1950s 1940–1955 Picnic Party at Subtropical Gardens, circa 1950s 1945–1960 Alpine Gorge with Chapel, Central European Mountain Valley, 1950s 1948–1960 Mountain Resort Lodge with Alpine Forest, Circa 1950s 1945–1960 Mountain Road Construction, Alpine Region, circa 1950s 1945–1960 Mountain Valley Viewed from a Tunnel Window, Mid-20th Century 1945–1965 Spanish Colonial Courtyard with Bougainvillea, 1950s 1948–1955 Formal Garden Border, ca. 1940s–1950s 1940–1955 Child with Toy Drum Set, circa 1950s 1948–1958 Lakeside Pavilion Interior, Summer c. 1950s 1945–1960 Manhattan Waterfront from Bridge, Mid-20th Century 1945–1955 Mediterranean Courtyard with Blue Column and Hydrangeas, circa 1950s 1945–1965 Formal Garden with Massed Plantings, Mid-20th Century 1945–1965 Tourist at Classical Ruin with Evergreen Shade, 1950s 1948–1958 Industrial Waterfront, Northern Europe, circa 1950s 1945–1960 Motorboat Bow Spray, Great Lakes, 1940s 1940–1950 Mountain Valley with Glacier-Fed River, Northern Rockies, 1940s 1940–1950 Alpine Garden with Pool and Perennials, mid-20th century 1945–1965 Swimmers at River Beach, ca. 1950s 1945–1965 Midnight Mass Altar Setup, Candlelit Church Interior, circa 1950s 1945–1960 River in Autumn, Northern New England, circa 1950s 1948–1958 Mountain Valley Town View from Garden Overlook, 1940s 1940–1950 Mountain Stream through Old-Growth Forest, circa 1950s 1945–1960 Twilight on a Frozen Lake, Northern Forest, circa 1950s 1945–1960 Mountain River Valley, Pacific Northwest, circa 1950s 1945–1960 Moose in River, Northern Wilderness, circa 1940s 1940–1955 River Valley Landscape, Central Europe, circa 1950s 1948–1965 Hilltop Town in Snow, Central Europe, circa 1950s 1945–1960 Ice-Laden Bluff, Lake Michigan Winter 1948–1965 Modernist Institutional Garden, circa 1950s 1948–1958 Aerial View of Rural Landscape with River, 1940s 1940–1950 Desert House with Parked Cars, American Southwest, circa 1950s 1948–1960 Logged Forest with Stream, circa 1940s–1950s 1940–1955 Tree-Lined River, Midwestern Waterway, circa 1950s 1945–1965 Midwest Farm Field, Spring Planting, circa 1950s 1945–1960 Public Park with Tramway, circa 1950s 1945–1960 Birch Forest, Summer, mid-20th century 1940–1960 Forest Camp or Lodge with Tall Pines, Mid-20th Century 1940–1955 Balanced Rock Formation, High Desert Landscape, 1950s 1945–1960 Badlands Erosion Study, Western United States, circa 1940s 1940–1949 Rural Rodeo Ground with Irrigation Pond, Western United States, 1940s 1940–1950 Mountain Valley Landscape, Pacific Northwest, 1940s 1940–1950 Hiker at Rocky Stream, Boreal Forest, circa 1950s 1942–1959 Arid Valley Landscape, Mid-20th Century Survey 1945–1955
certain inferred low confidence