Voices of the Rocks: A Scientist Looks at Catastrophes and Ancient Civilizations

Robert M. Schoch's 1999 book (Harmony) consolidates his geological argument for the redating of the Great Sphinx of Giza on the basis of weathering patterns. Schoch, a geologist at Boston University, has argued since the early 1990s that the Sphinx's substantial rain-erosion features indicate a date significantly earlier than the conventional Old Kingdom attribution (c. 2500 BCE) — possibly as early as the Pre-Dynastic period or the late Pleistocene. The specific claims about the Sphinx remain contested in academic Egyptology; the broader argument about pre-Flood civilization places Schoch within the catastrophist-civilization tradition.