1888-1891. Earliest photograph recording glyphs in front of snout above. The date is usually interpreted as equivalent to A.D.862.       
1888-1891 photograph by Henry N. Sweet as a member of the Thompson/Peabody expedition; scanned from 35mm slide of original photograph at Dumbarton Oaks. Reproduced Courtesy of the Peabody Museum of Archaeology and Ethnology, Harvard University.