Mask stack over doorway 4 (incorrectly identified as doorway 5 in Seler caption). "Fig. 60. Uxmal. House of the Nuns. North building. Inner or main facade (south front). First through third masks (from below) of mask column C above the fifth door (counting from the west end )."
Scanned from Eduard Seler, “Die Ruinen von Uxmal,” 1917 (fig. 60).