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.
Klosterkreuzgang mit zwei Nonnen, Colombia oder Ecuador, Mitte 20. Jahrhundert 1940–1970 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 Alpine Valley Resort or Mountain Lodge, Early Color Film, circa 1950s 1948–1958 Aerial View of Bay and Waterfront, Mid-20th Century 1948–1965 German River Town at Dusk, circa 1950s 1948–1958 Mountain Pass Through Alpine Forest, Mid-20th Century Kodachrome 1945–1965 Limestone Quarry or Strip Mine, Mid-20th Century American West 1940–1970 Suburban Waterfront, Midwest Lake City, circa 1950s 1945–1960 Industrial Waterfront, Florida, 1940s-1950s 1940–1955 Mediterranean Coastal Inlet with White Limestone Cliffs, circa 1950s 1945–1960 Tourists at a Mountain Gorge with Cascading Waterfall, Early Color Photography 1940–1955 Manhattan at Night, circa 1940s-1950s 1940–1955 Rural Homestead with Crepe Myrtles, American South, circa 1940s-1950s 1940–1955 Formal Garden with Italian Cypress and Weeping Trees 1940–1960 Thatched House with Stream and Ivy, Britain, circa 1940s–1950s 1940–1955 Pine Forest and Stone Tower, Mid-20th Century American Landscape 1940–1960 Birch trees and lake, Canadian Shield region, autumn 1940s–1950s 1945–1955 Flower Show Display Garden, Mid-20th Century 1945–1965 Rural riverside homestead, American Midwest, mid-20th century 1940–1960
certain inferred low confidence