The 1850s through early 60s was a transformative period for nascent studies of the remote human past in Britain, across many disciplines. Naturalists and scholars with Egyptological knowledge fashioned themselves as authorities to contend with this divisive topic. In a characteristic case of long-distance fieldwork, British geologist Leonard Horner employed Turkish-born, English-educated, Cairo-based engineer Joseph Hekekyan to measure Nile silt deposits around pharaonic monuments in Egypt to address the chronological gap between the earliest historical and latest geological time. Their conclusion in 1858 that humans had existed in Egypt for exactly 13,371 years was the earliest attempt to apply geological stratigraphy to absolute human dates. The geochronology was particularly threatening to biblical orthodoxy, and the work raised private and public concerns about chronological expertise and methodology, scriptural and scientific authority, and the credibility of Egyptian informants. This essay traces these geo-archaeological investigations; including the movement of paper records, Hekekyan's role as a go-between, and the publication's reception in Britain. The diverse reactions to the Egyptian research reveal competing ways of knowing the prehistoric past and highlights mid-Victorian attempts to reshape the porous boundaries between scholarly studies of human antiquity.