Photo crop exposure date: unknown. Exposure date (or window) of subject photo: ca. 1877. Subject: photo crop of Gallagher building (1877). US Post Office on first floor. View ESE from across the Blum and Alamo intersection. No streetcar rails (service begins 1878) can be detected in the photograph and the Sanborn maps indicate that the buildings just south have awnings which are not present in the photograph. Therefore the subject photograph is dated from building completion.