1859-60; 1862. Earliest photograph of this famous section of the frieze; showing the mask stack, serpents and other parts remarkably well preserved.
Photograph mounted in Désiré Charnay, Cités et Ruines Américaines, 1862; taken by Charnay 1859-60. This image scanned from a 35mm slide taken from a copy in the AMNH (RF-106-D). Reproduced Courtesy of The Library, Special Colections, American Museum of Natural History.