This primary source comes from the Records of the Office of the Chief of Engineers.
National Archives Identifier:
519491Full Citation: Comstock Lode. Virginia City, Nevada; ca. 1867 - 1868; Records of the Office of the Chief of Engineers, Record Group 77. [Online Version, https://www.docsteach.org/documents/document/comstock-lode-virginia-city-nevada, May 14, 2024]