[The following is IL's synopsis of Colin Reader's paper. It is an extended version of the commentary which appeared in the original Epilogue of the paperback edition of Giza: The Truth in 2000.]

By far the most revealing new piece of research to come to our attention recently is that of British geological engineer Colin Reader on the age of the Sphinx. Although his paper Khufu Knew the Sphinx remains self-published at the time of writing, it was immediately apparent to us that he had some new ideas which deserve serious consideration. Unlike John Anthony West and Robert Schoch, he does not attempt to push the age back by more than a few hundred years - in fact only to the early dynastic period c. 2800 BC - and moreover he does make a considerable effort to fit his revised chronology into the proper archaeological context of Giza as a whole. Reader's paper is relatively long and contains some complex analysis - indeed our subsequent correspondence with him is similarly lengthy - but the essential points can be distilled as follows.

There are two primary pieces of evidence which Reader suggests force us to consider a pre-4th Dynasty date for the monument, neither of which as far as we are aware have been properly elucidated elsewhere. The first forms the basis for his refutation of Lal Gauri's chemical weathering hypothesis which we previously supported. He draws our attention in particular to the distribution of weathering patterns between the western Sphinx enclosure wall and the rump of the monument itself, indicating that whereas there is significant widening and rounding of the vertical joints in the enclosure wall, there is little evidence of this in the rump. In our correspondence we pressed him hard on whether he was comparing "like with like", and although we all accept that better evidence of the weathering underneath the repair blocks on the rump would improve our understanding, nevertheless it is clear that in the unrepaired strata immediately above the blocks (referred to as "unit 3ii") there is minimal widening and rounding of the vertical joints. In fact we questionned whether these joints - which were originally sub-surface geological fault lines - really did continue into the body of the monument at all, but Reader provided us with evidence from one of Gauri's own papers (Gauri, Geologic Study of the Sphinx, NARCE 127) that they do. Since the strata to which we are referring are the same in both locations, and there is only approximately 20 metres distance between the wall and the rump, and since chemical weathering depends primarily only on air temperature and humidity, he contends that some other weathering agent must be responsible for the differentiated patterns observed on the enclosure wall - and that that agent is surface water run-off. According to him, surface water run-off is known to have been experienced at Giza and, for example, has been cited as the cause of damage to the Third Pyramid's valley temple.

Figure 1: The Joints in the Sphinx Enclosure; and the Khufu & Khafre Quarries

Reader's second observation concerns the quarry used by Khufu's builders as the main source of limestone for the Great Pyramid. It is clear from Figure 1 that this quarry eventually occupied virtually the entire space between the Second Pyramid and the Sphinx enclosure - albeit that there is a suggestion that it was extended significantly to the west during Khafre's reign. It is also clear that once used this quarry would have been back-filled with limestone chips and other debris from the construction process. He suggests that as soon as this quarry was excavated, and even once it had been back-filled, it would have all but eradicated the ability of rain water to run-off from the previously extensive catchment area to the west of the Sphinx enclosure. This is because, for surface run-off to occur, the rate of rainfall must exceed the rate at which the surface and immediate sub-surface can absorb it, and sporadic but heavy rainfall prior to the quarrying would have quickly exceeded the ability of the original limestone bedrock to absorb it. By contrast the rainfall would have to be far more intense to achieve run-off over the significantly more permeable in-fill of chippings and wind-blown sand after quarrying and back-fill had taken place; and even then run-off would only occur if the various fills reached the original level of the limestone across all parts of the quarry - otherwise the run-off would be halted by the eastern quarry wall, or at least by some form of ascent out of the dip created by the only partially back-filled quarry. He suggests that just such a dip does form part of the post-quarry topography.

Reader goes on to argue that his case is strengthened by a close analysis of the north enclosure wall. He points out that there is a significant and clear break between the weathered surface of the bulk of this wall and the vertical and non-weathered portion which lies at its eastern end - in fact that portion which has been quarried immediately adjacent to the north wall of the Sphinx Temple. He further points out that, whilst there is no doubt that the bulk of this temple is contemporary with the carving of the Sphinx because the blocks can be matched with the appropriate strata in the Sphinx enclosure, there is room for doubt about the source of the blocks for the Valley Temple (with which assertion we now agree). Whilst we have previously argued strongly against any attempt to suggest a two-stage construction for the Valley Temple, and continue to so do, Reader's suggestion of a two-stage construction for the Sphinx Temple should not be lightly dismissed. He argues that the a smaller version was constructed at the time the Sphinx was carved, which was then extended to the north and south during the 4th Dynasty - hence the relatively unweathered "new" enclosure wall to the north.

To complete his analysis, he suggests that a portion of the Second Pyramid's mortuary temple may also have been originally constructed along with the Sphinx and Sphinx Temple, only to be extended later, and that the two proto-temples formed the eastern and western elements of a complex clearly designed in early or even pre-Dynastic times as part of a solar cult. This would explain why it was Khaf-re, not Khufu, who extended these existing structures and incorporated them into his pyramid complex - as part of the reemergence of the solar cult. He backs up his assertions by listing a number of pieces of published archaeological evidence for activity at Giza from as early as the late pre-Dynastic period.

Although we are by necessity significantly abbreviating Reader's analysis, this is the nub thereof, and we find it at worst stimulating and at best downright persuasive. We await further research by him, and indeed feedback from others who may be able to spot weaknesses in his arguments which we have not. However at present we have really only one "bone of contention" left with him, and it concerns the Sphinx's face. We have indicated previously that we feel there is indeed a significant likeness between this and the statue of Khafre housed in the Cairo Museum, and Reader is inclined to agree with our analysis. He had already concluded that the Sphinx was originally carved probably with a lion's head, and then recarved in the 4th Dynasty, possibly by Khafre, on the basis of two pieces of evidence. First, the disproportionately small size of the head of the monument in relation to its body; and second, the extent of preservation of the details on the head, which - albeit that it is carved from more durable Member III limestones - he feels is because in its recarved form it had hardly any time to be exposed to the harshest chemical weathering which occurred during the wettest climatic conditions pre-2350 BC (remember that chemical weathering is itself at its most aggressive in conditions of high humidity - he applies the same logic to the relatively unweathered enclosure wall to the north of the Sphinx Temple). Reader backs up this assertion by suggesting that a number of recumbent lion statues have been found dating at least as far back as the First Dynasty.

Our argument with him in this area can be split into two parts: First, we should revisit our own assertion that there is indeed a strong resemblance between the face of the Sphinx and Khafre's statue. After all, if this is false, then there is no need to suggest that the Sphinx's face was recarved. Indeed although, like Reader, West and Schoch both believe that the head probably has been recarved because of its relative size, which makes their insistence that there is no resemblance somewhat confusing, they have accused us publicly of "short-changing" Frank Domingo's forensic reconstruction work. In fact we pulled our punches somewhat, because we had reproduced his reconstructions and found that, if the Sphinx's face is tilted forwards so that it presents a similar profile angle to that of the statue, the profile of the eyes, nose and lips is remarkably consistent, even if their relative positions do not match exactly. We did not include these reproductions in our book lest we be accused of manipulation of the evidence - and frankly we already thought our case strong enough. But in the light of Reader's new research and West and Schoch's accusations, they are now shown in Figure 2.

Figure 2: Reconstructed Face of the Sphinx Compared with that of Khafre
(After Domingo in West, Serpent in the Sky, Appendix II, pp. 230-1)

Readers will decide for themselves the extent to which this comparison supports our contention that the faces are one and the same, and whether or not our simple tilting of one profile constitutes manipulation of the evidence. Those that are happy with our assertions will, like us, ponder the likelihood of the monument's face having been recarved by Khafre. Despite the relative size of the head, to us this explanation just does not "feel" right. Let our critics attack us for the lack of scientific method in such a statement, but it is our best judgement. Accordingly, the age of the Sphinx remains, in our view, an open question.

Although we now accept that there may be reason to question Gauri's chemical weathering hypothesis, Reader's redating is significantly less than that proposed by Schoch, let alone that of West, and involves pushing the age back by no more than 300 or so years. This is based primarily on respect for the archaeological context, and as a result requires assumptions about the ability of the heavier rainfall pre-2350 BC, and especially pre-Khufu, to effect sufficient weathering. In our view this is a more reasonable approach than Schoch's use of seismic surveys to suggest a much older date (for our critique thereof see Giza: The Truth, Chapter 7, pp. 324-7), while West's attempts to push the date back even farther have no contextual or logical grounding other than the readings of Edgar Cayce and Bauval's astronomical "lock" on 10,500 BC.