Abstract The Mary M. Marks photograph collection consists of approximately 301 glass plate negatives (with modern paper prints) and 24 prints without negatives. The images are from the Oro Grande Placer Mine and the Gold Pan Mining Company on the Blue and Snake Rivers in Colorado and include mining pits, dredges, flumes, ditches, and surveying/engineering parties. Other images are of railroad depots and homes in Summit County Colorado (Breckenridge and Dillon). Also included are images of Mary, her...