68. Down through Hell's half mile.
MLA
Canyon, Colorado, et al. 68. Down through Hell's Half Mile. 1908. https://collections.library.yale.edu/catalog/2017887.
APA, 6th edition
Canyon, C., Pacific Railway Survey, S., & R. B. (1908). 68. Down through Hell's half mile. [Photographic prints, Photographs]. https://collections.library.yale.edu/catalog/2017887.