A Reconciliation of the Geological and Archaeological Evidence for the Age of the Sphinx and a Revised Sequence of Development for the Giza Necropolis.

Colin D. Reader Oct 97 (Revised Aug 99)*

[This is the text of an excellent paper written by Colin Reader - unfortunately limited space means we have been unable to reproduce his figures, although simplified versions of two key ones are reproduced in our synopsis/response which follows.]

* I am extremely grateful to Robert B. Partridge, author of "Faces of Pharaohs" and "Transport in Ancient Egypt", for encouraging me to write this paper and for developing my initially sketchy ideas concerning the likely influence of theology on the proposed development of the Giza necropolis.


In 1992, a Boston University Professor of Geology, Robert M. Schoch, published a paper which concluded that the Great Sphinx of Giza was carved at a time between 5000 and 7000 BC1. This conclusion was reached following a study of the degradation of the body of the Sphinx and adjacent exposures. Schoch stated that the ".....rolling and undulating vertical profile to the weathered rocks ....." was attributable to "...precipitation-induced weathering".

The Sphinx is conventionally attributed to the Fourth Dynasty pharaoh, Khafre (ca. 2520 - 2494 BC2) and, unsurprisingly, Egyptologists rejected Schoch's early date. Schoch's work has also been criticised, however, by a number of geologists, notably Dr. J.A. Harrell3 and Dr. K.L. Gauri4, who have offered alternative interpretations of the degradation of the Sphinx in support of its generally accepted Fourth Dynasty construction.

Harrell attributed the degradation of the Sphinx and the adjacent exposures to the so-called "wet-sand" hypothesis - in which the exposed limestone, buried in accumulations of wet sand, has been subject to chemical weathering. The processes Harrell described to promote the wetting of accumulated sand within the Sphinx enclosure, however, do not stand up to detailed scrutiny5 and, on this basis, the wet-sand hypothesis is regarded as largely untenable.

The paper by Gauri et al4 provides a summary of many of the features of degradation that are present along the body of the Sphinx and adjacent exposures, attributing these features to the combined effects of sub-surface groundwater movement and chemical weathering. I consider, however, that these processes, although significant, are unable to account for all the features of degradation that are present within the Sphinx enclosure.

I have, therefore, undertaken a review of the geology, geomorphology and surface hydrology of the Giza necropolis which has led to a revised sequence of development for the site. In this way, and by considering the development in the use of stone masonry in Ancient Egypt, it has been possible to reconcile the geological and archaeological evidence whilst placing the construction of the Sphinx within the context of Dynastic Egypt.


The geology of the Upper Mokattam Limestones, from which (and on which) the Giza necropolis was constructed, has been described at length by others6,7,8. The original ground surface at Giza has been controlled by the south-easterly dip of the strata (5o to 7o), with the Sphinx occupying a position at the low lying, eastern edge of the plateau. Detailed geological mapping of the Sphinx enclosure, undertaken by Gauri6, has led to the adoption of a system of reference for the exposed strata, summarised below and on Figure 1.

The strata exposed at the Sphinx have been divided into three members. The lowest, Member I, consists of a massive and durable reefal limestone, exposed across much of the base of the Sphinx enclosure. The lowest lying parts of both the body of the Sphinx and the western exposures consist of Member I strata, with the quarried height increasing up-dip, towards the north west. The entire northern exposure consists of Member I limestones.

The upper body of the Sphinx and the upper part of the adjacent exposures to the south and west, consist of the overlying Member II strata, a cyclothemic series of seven fine grained limestone units which, generally, become more durable towards the top of the sequence. Of these seven units, units 1 to 6 have been further divided into two sub-units, the lowest of which consists of a less durable, marly rock and is identified by the Roman numeral i. The upper more durable sub-unit is identified by the Roman numeral ii.

The head and neck of the Sphinx are carved from perhaps the only Member III exposure at Giza6 which, on the basis of durability, has also been divided into two sub-units. The neck of the Sphinx consists of relatively less durable rocks, whereas, the head has been carved from one of the most durable units of the Upper Mokattam formation (the durability of the Member III strata has been cited by others to explain the remarkable preservation of the Sphinx's face and Nemes head-dress).

The durability of the Upper Mokattam Limestones is controlled by two intrinsic properties of the rock - the pore size distribution and the salt content of the pores4 - with durability influencing the development of sub-vertical discontinuities within the strata. The exposed rock is cut by two sets of irregularly spaced, near-vertical, intersecting joints which, although well-developed in the more durable strata, become less distinct in the softer units.


A number of Egyptologists have argued that the Sphinx was carved from a block of limestone, left-over from quarrying of the site undertaken during the reign of Khufu. This 'quarry-block' hypothesis assumes that originally, ground levels at Giza were above the level of the head of the Sphinx and were reduced by extensive Fourth Dynasty quarrying. However, quarrying on this scale would represent a gross modification to the Giza landscape and is not consistent with the extent of quarrying that has been established by archaeological investigation of the site9.

Other Egyptologists have argued that, as an integral part of Khafre's mortuary complex, the site of the Sphinx was dictated by the layout of adjacent features, such as the Sphinx temple, Khafre's valley temple and Khafre's causeway. Like the 'quarry-block' hypothesis, however, this proposition also neglects the influence of natural processes on the development of the Giza plateau.

Natural processes were considered by El-Baz10, who saw the Sphinx as a yardang (a knoll of rock sculpted by wind blown sand) that had been 'dressed-up' during the Fourth Dynasty development of the site. Other, similar propositions suggest that the Sphinx is " isolated karst residual hill..."11. However, as the body of the Sphinx lies within an excavation - an artificial feature - Egyptologists have generally regarded the theories of El-Baz et al as untenable1.

There is, however, evidence to indicate that the general topography of the Giza plateau is the result of natural processes. As discussed by Thomas Aigner12, the Giza area was inundated by a landward advance of the Mediterranean sea during the Pliocene (2 to 7 million years ago). The erosion caused by this inundation was controlled largely by the south-easterly dip of the Upper Mokattam Limestones and resulted in the formation of the plateau, much as we see it today, bounded by a number of north- and eastward facing raised cliff-lines.

In addition to the evidence presented by Aigner, I consider there to be a number of other features which indicate that the location of the Sphinx was determined by the topography of the site, with the head of the Sphinx excavated from a locally elevated body of rock:

  • To the south of the Giza necropolis is the "Main Wadi"13 (Figure 2), with the area between the "Main Wadi" and the Sphinx occupied by a number of tombs, the eastern part of the Central Field cemetery. Although this area has been modified by ancient quarrying and construction, it is possible to discern the original ground profile from the remaining features - with ground levels increasing to the north and west towards the Sphinx14 (Plate 1).

  • To the north of the Sphinx, a modern tourist road runs east/west along the foot of a rock face into which a number of tombs have been cut (Figure 3). The state of weathering and erosion of this rock face, and its continuity with the Pliocene cliff line that defines the eastern limit of the Giza plateau12, indicates that this is a naturally eroded feature, which I consider to be the northern bank of a second smaller wadi (the "Lesser Wadi" - Figure 2 and Plate 2i).

  • A section through the southern bank of the "Lesser Wadi", may be preserved in the extreme north west corner of the Sphinx enclosure, at the position where the western enclosure wall meets the retaining wall that supports the modern road (Figure 3 and Plate 2ii). At this location, the rock-head that defines the top of the western Sphinx exposure drops sharply beneath accumulated sand, with the resulting depression filled with modern masonry. The rock-head profile within this depression is rounded, suggesting that this is a natural feature rather than the result of quarrying, for which a stepped profile would be expected.

Collectively, these geomorphological features indicate that the layout of the eastern end of Khafre's mortuary complex was determined on the basis of the local topography. Original ground levels rose from the "Main Wadi" in the south, to a high point in the vicinity of the Sphinx. The mass of rock from which the Sphinx was later to be carved, was isolated from the northward continuation of the plateau (the area of Khufu's pyramid) by erosion along the "Lesser Wadi". The resulting outlier, capped by durable Member III strata is likely to have preserved the steepened profile of the Pliocene cliff line on its eastern flank and, consequently, may have been particularly prominent when viewed from the Nile valley.


Of the three members of the Upper Mokattam Limestone, much of the debate on the age of the Sphinx has concentrated on the degradation of the Member II strata, which is best represented and most widely distributed within the Sphinx enclosure. Examination of this strata has established that the degradation present is characterised by three principal features:

  • sub-horizontal degradation - parallel with the bedding plane;

  • sub-vertical degradation - across the bedding plane;

  • receded strata at the top of the exposures.

On the basis of the distribution of these features, the exposed strata can be divided into four areas (Figure 3):-

A. The body of the Sphinx: Much of the Member I and lower Member II strata, from which the body of the Sphinx has been carved, is obscured by masonry which has been used to restore the profile of the statue. A number of phases of restoration are believed to have been carried out, with the earliest thought to date from the Old Kingdom15 and the latest completed recently. The exposed upper strata is dominated by the rounded, sub-horizontal degradation indicated on Figure 4a. This is considered to be the result of differential degradation of the exposed strata, with the less durable units (3i, 4i, 5i) receding somewhat from the original cut profile. Relatively few sub-vertical degradation features are present and, other than the "Main Fissure", which cuts through the body of the Sphinx just forward of the hind quarters (Figure 3), those that are present are generally poorly defined and limited in extent.

B. The eastern end of the southern exposure: As remarked by Dr. Mark Lehner16, the profile of the cut face at this location is preserved in much its original form. A likely reconstruction of this original profile is given on the geological section in Figure 4b. Sub-horizontal degradation of the less durable units (2i, 3i and 4i - Figure 4b) is evident and these have receded somewhat from the original cut profile. A small number of sub-vertical discontinuities, of probable tectonic origin (exposed joints etc.), can be identified cutting the full height of the face. In addition, a series of poorly defined sub-vertical degradation features can also be identified, which are largely restricted to the upper section of unit 3ii. The upper part of unit 3ii, together with units 4i and 4ii, exhibit a slightly rounded, somewhat receded vertical profile.      

C. The western end of the southern exposure: The only geological section published by Gauri for the southern exposure is that referred to above (Figure 4b). However, inspection of the entire southern exposure has shown that the sub-vertical degradation features become progressively more frequent and more extensive towards the west (Figure 4c). At the extreme western end of the exposure, these sub-vertical features are more deeply incised than those to the east and extend across the full height of the exposed face.

D. The western exposure: On the geological section on Figure 4d, a conservative reconstruction of the original cut face of the western exposure is proposed, in the manner suggested by Lehner for B above. From this reconstructed profile, it can be seen that, not only is the sub-horizontal degradation of the less durable, marly units (1i, 2i and 3i) more pronounced than elsewhere, the more durable units (1ii, 2ii and 3ii) have also been substantially modified.

There is an increased frequency of sub-vertical degradation features along the western exposure and these are, generally, more deeply incised than elsewhere. This deep degradation has led to the development of the rounded lateral profile, or 'coved' appearance described by Schoch. In places the sub-vertical features combine in a dendritic pattern, indicating that even minor discontinuities in the exposed strata have been exploited. When compared with the reconstruction of the original cut profile, the upper-most units (3i, 3ii, 4i and 4ii) can be seen to have receded considerably.

It is evident that much of the body of the Sphinx and the eastern end of the southern exposure exhibit comparatively moderate degradation - typified by sub-horizontal degradation and limited erosion of the upper strata of the enclosure walls. However, by comparison of the same units at different locations within the Sphinx enclosure (Figures 4b and 4d - with sections drawn to the same scale), it can be seen that in the west, the degradation of the enclosure walls becomes more intense, with deeply incised sub-horizontal and sub-vertical features and substantial modification of even the most durable units (1ii, 2ii and 3ii - Figure 4d). This distribution in the intensity of degradation has not been recognised by Gauri et al17 and I consider that, with respect to the age of the Sphinx, it is particularly significant.


Gauri et al4 attribute the degradation of the Sphinx enclosure primarily to the effects of chemical weathering and exfoliation - in which dew, forming at night on the exposed limestone, removes soluble salts from the surface of the rock. Capillary forces draw this solution into the pores of the limestone matrix, where further salts are dissolved from the internal pore walls. As daytime temperatures rise, the solution begins to evaporate - precipitating salt crystals within the confined neck of the pores. The pressure that these crystals exert as they grow, leads to stress-induced exfoliation from the surface of the limestone.

This process can be assumed to have operated throughout much of the accepted history of the Sphinx - certainly since the prevailing arid climate became established - and has led to the development of "the vertical profile of the Sphinx and the walls of the Sphinx enclosure made of alternating projections and recessions"4. What is most significant, however, is that with the limestones exposed to chemical weathering and exfoliation, the development of this vertical profile will have been controlled by the bedded nature of the rocks, with the less durable units (those identified by the Roman numeral 'i') receding further from the cut face than the interbedded more durable strata.

Although the bedding of the strata will have influenced the development of the vertical profile, it will have had no influence on the development of the more intense degradation in the west of the Sphinx enclosure. As Figures 4b, 4c and 4d illustrate, this lateral variation is independent of the bedding, with degradation becoming more intense along, rather than across, the exposed beds. As it has not been controlled by the bedding, I consider that the development of the lateral variation can not be interpreted in terms of the processes of chemical weathering and exfoliation described by Gauri et al.

I consider that Gauri et al also fail to account for the distribution of sub-vertical degradation features within the Sphinx enclosure - features which they attribute to two quite separate processes:

  • the pre-Pliocene movement of groundwater along joints. This occurred long before the excavation of the Sphinx and will have led to the widening of joints by the solution of limestone;

  • the selective degradation of joints by chemical weathering and exfoliation. This can only have occurred after the joints were exposed by the excavation of the Sphinx.

A number of the most significant sub-vertical features, exposed along the western enclosure walls, have been plotted on Figure 3. By measuring the orientation of these exposed joints and then extrapolating their axes across the Sphinx enclosure, it can be demonstrated that a number of these joints pass through the body of the Sphinx18. Given the established joint distribution and alignment, I consider that any solution-widened joints, intersected by the excavation of the Sphinx, would be exposed in pairs, with open joints on both the western enclosure walls and, across the excavation, on the adjacent body of the Sphinx.

By reference to unit 3ii (exposed on both the western enclosure walls and the rump of the Sphinx - just above the restorative masonry) it is evident that this expected distribution is not present. Along the western enclosure walls, the sub-vertical degradation features are numerous, deeply incised and persistent (Figure 4c and 4d), however, no significant sub-vertical degradation features can be identified along unit 3ii on the rump of the Sphinx (Figure 4a).

Photographs taken of the rump of the Sphinx in the early 1980s19, when the restorative masonry was at a lower level, show that units 3i and 2ii are also, generally, free from sub-vertical degradation features. The only exception to this, is a single sub-vertical feature which I do consider to be a solution-widened joint.

On the basis that the large number of sub-vertical degradation features exposed along the western enclosure walls, generally, do not have any corresponding expression on the rump of the Sphinx, I consider that they can not be interpreted as solution-widened joints. Furthermore, the distribution of degradation suggests that the other mechanism proposed by Gauri et al - chemical weathering and exfoliation - also fails to account for the development of the sub-vertical degradation features within the Sphinx enclosure:

The intensity of chemical weathering and exfoliation is influenced by two principal factors - air temperature and humidity. Given that these factors will exhibit only slight variation over the 20m or so that separates the body of the Sphinx from the western enclosure walls, I consider that the weathering of joints by these processes would not lead to the development of the marked distribution that is present20.

I do not dispute that the processes of chemical weathering and exfoliation have been responsible for weathering of the Member II strata within the Sphinx enclosure. It is also evident that a small number of sub-vertical degradation features can be interpreted as solution-widened joints. However, I consider that these processes can not account for the increased intensity of degradation along the western enclosure walls, nor the marked distribution of sub-vertical degradation features that exists between the western exposures and the body of the Sphinx. It is concluded, therefore, that the features of degradation within the Sphinx enclosure are the result of a more complex degradational history than that proposed by Gauri et al and, to investigate this further, it is necessary to reconsider the climatic and other conditions that have been experienced at Giza.


Although arid conditions have dominated the dynastic period of Egyptian history, wetter periods are known to have been experienced, with the current arid conditions not becoming fully established until as late as ca. 2350 BC21 (i.e. until the late Fifth Dynasty). The rainy conditions of ca. 5000 to 7000 BC, to which Schoch attributed the degradation of the Sphinx, will have been separated from these later arid conditions by a transitional phase, during which increasingly arid conditions will have been interrupted by occasional, probably seasonal rains.

With limited vegetation or sub-soil cover at Giza, sporadic heavy rainfall would have quickly saturated the upper strata, leading to run-off over the plateau towards the Nile valley. Although these rain storms would have been of short duration, the momentum gained by run-off across extensive areas can produce surface flows capable of significant erosion. Flood damage to Menkaure's valley temple22 attests to the fact that, during the Old Kingdom, rainfall run-off was a significant agent of erosion at Giza.

Given the topography of the site, rainfall run-off from the Giza plateau will have discharged towards the lower lying areas in the east, with the erosive potential of this discharge depending, amongst other things, on the size of the available catchment. Given the orientation of the Sphinx enclosure, much of the local run-off will have discharged over the western exposures, eroding the exposed limestone and selectively exploiting any joints exposed along the cut face.

Comparatively little run-off will have discharged over the exposed faces in the east and, consequently, the erosion of the eastern exposures will have been less intense. The series of short, ill-defined sub-vertical degradation features, identified along the upper part of unit 3ii (Figure 4b), illustrates the influence that the position and orientation of an exposure can have on the resulting erosion. Although both the eastern and western exposures are of the same age, the degradation that has developed is significantly more intense in the west - the exposures over which most rainfall run-off will have discharged.

The body of the Sphinx will have generated little run-off itself and will have been isolated from run-off from the plateau, by the surrounding excavation. The general absence of sub-vertical degradation features along the body of the Sphinx is, therefore, consistent with the action of rainfall run-off that I propose.

It is evident that, when the erosive potential of rainfall run-off is considered (in addition to the effects of groundwater movement, chemical weathering and exfoliation) a comprehensive interpretation of the degradation within the Sphinx enclosure can be made, which is consistent with the observable features and can account for both the more intense degradation in the west of the Sphinx enclosure and the marked distribution of sub-vertical degradation features.

As both the reconstructed climate of the period and the archaeological record indicate, however, Giza was subject to rainfall and rainfall run-off during the Fourth Dynasty. It is, therefore, evident that the erosion of the western Sphinx exposures by run-off does not, in itself, require a revision to the Fourth Dynasty origin of the Sphinx.


In his paper "The Development of the Giza Necropolis: The Khufu Project", Lehner modelled the development of Khufu's mortuary complex, paying particular attention to the temporary works (quarries, ramps, accommodation etc.) which were a vital element of the construction programme.

Significant to the current discussion, is a quarry23, located to the west of the Sphinx and to the north of Khafre's causeway (Figure 2). The position of this quarry can be identified today by a low depression in the surface of the plateau, filled with accumulations of wind blown sand.

Archaeological excavation in the eastern end of this quarry has identified a pair of closely spaced, parallel walls, built along the floor of the quarry from rough masonry faced with clay24. These walls have a general north-south alignment and show a slight slope up towards the cemetery to the east of Khufu's pyramid. Given their location and orientation, these features have been interpreted by Lehner as part of a construction ramp used during the development of Khufu's mortuary complex. This date has been confirmed by mud seal impressions, bearing the name of Khufu, which were found in debris excavated from between the walls. This evidence securely dates the working of this quarry to the reign of Khufu.

From the earliest phase of Khufu's development, this quarrying will have disrupted the surface hydrology of the site, with the open excavation intercepting any run-off from the higher plateau in the west and preventing its discharge towards the area of the Sphinx.

Although worked during the reign of Khufu, Lehner has argued that the quarry was extended to the west during the reign of Khafre. As these additional areas of quarrying were opened up across the plateau, mud brick from construction ramps and large volumes of chippings from the working of masonry may have been deposited in the earliest, worked-out areas. It is not clear how quickly wind-blown sand then accumulated over this construction debris, however, the surface hydrology of the backfilled quarry will have been very different from that of the intact limestone plateau that preceded it.

Rainfall run-off will only be generated when the surface and immediate sub-surface becomes saturated. This occurs when the rate of rainfall exceeds the rate at which water can drain through the sub-surface soils or rocks (the permeability). Given the fine-grained nature of the limestones and the presence of relatively impermeable marly horizons within the Member II strata that form the surface of the plateau, saturation is likely to have been achieved under comparatively moderate rainfall conditions. By contrast, the higher permeabilities of the unconsolidated windblown sand, within the abandoned quarries, will have required significantly more extreme rainfall conditions before the sub-surface reached saturation.

I consider it unlikely that rainfall experienced at Giza will have been of sufficient intensity to generate run-off from the backfilled quarry. Even if such extreme conditions were encountered, however, the discharge of rainfall run-off from the quarried areas, would depend on a number of additional factors. Unless the backfill and accumulated sand reached the level of the unworked limestone that surrounds the quarry, any run-off that was generated will have been prevented from discharging towards the Sphinx by the eastern quarry face. For any post-Khufu erosion to have taken place, therefore, it would be necessary for the quarried areas to have been backfilled to the original level of the plateau before the end of the Fifth Dynasty (i.e. before the onset of the present arid conditions). Even then, however, discharge towards the Sphinx would depend on a suitable pattern of surface drainage across the quarry backfill.

In accordance with the conventional sequence of development, the excavation of the Sphinx post-dates the construction of Khufu's pyramid and the working of the associated quarries. Given the effect of Khufu's quarries on the surface hydrology of the site, this sequence of development largely precludes the erosion of the Sphinx enclosure by rainfall run-off25 - yet I consider that without the action of this agent of erosion, it is not possible to fully account for all the features of degradation that are present within the Sphinx enclosure. On this basis, therefore, I conclude that the excavation of the Sphinx was undertaken some time before Khufu's quarrying began, when rainfall over the more elevated areas of the Giza plateau was able to run-off a substantial catchment, gathering momentum before finally discharging into the Sphinx enclosure.


A study of the distribution of fossils within the Upper Mokattam Limestones at Giza, has established that the masonry used to construct the Sphinx temple was quarried from within the Sphinx enclosure26. This indicates that the Sphinx and Sphinx temple were probably built at the same time which, given the geological evidence discussed above, suggests that both features pre-date Khufu's development of the site. There are, however, two principle sources of evidence which would appear to confirm the conventional Fourth Dynasty construction of the Sphinx and Sphinx temple:

  • archaeological excavation, undertaken within the Sphinx enclosure, encountered three large limestone core blocks within a mound of material supporting one corner of the Eighteenth Dynasty temple of Amenhotep II (Figure 3). According to Lehner and Hawass27, these blocks were left by the ancient builders " they were dragging them over to complete the core work on the corner of the Sphinx temple. One block rested upon debris containing numerous pieces of Fourth Dynasty pottery."

  • a tall vertical face, has been quarried in the Member I strata, immediately to the north of the Sphinx temple. This quarrying begins at a point aligned with the eastern face of the Sphinx temple, passes under the foundations of the Amenhotep II temple and extends westward to a position opposite the north forepaw of the Sphinx (Figure 3 and Plate 3i)28. This quarrying has been dated by Lehner and Hawass to the Fourth Dynasty on the basis of artefacts (including hammer-stones and pottery) that were found in a number of removal channels above the quarried face. These channels were part of the quarrying process and were excavated in order to isolate blocks of limestone for use as masonry.

Although this would appear to undermine my argument for earlier activity at Giza, there is evidence to suggest that this Fourth Dynasty activity represents only a limited phase of construction within the Sphinx enclosure and can not be used to date the original construction of either the Sphinx or Sphinx temple.

According to the Egyptologist H. Ricke, a 'seam' can be identified which runs through the masonry of all four corners of the Sphinx temple. This feature can be readily identified on the south east face of the structure, adjacent to Khafre's valley temple (Plate 3ii). According to Ricke, "this [seam] marked the outside of the walls of the temple in its first building phase. The north and south colonnades of the temple...were added after the interior of the temple had been largely finished with granite sheathing. For the addition, the middle part of the north and south walls were pushed back, and great limestone core blocks were added to the outside corners of the temple, which were never finished off"26.

Given that the abandoned core blocks, discovered under the Amenhotep II temple, were destined for the "...corner of the Sphinx temple" they are evidently part of Ricke's second building phase. On the evidence of the pottery found beneath the masonry, this second phase of construction, together with the limited quarrying to the north of the Sphinx temple, can be dated to the Fourth Dynasty.

Ricke does not speculate on the period of time that separated this Fourth Dynasty activity from the proceeding phase of Sphinx temple construction. However, on the basis of degradation of the limestones exposed within the Sphinx enclosure, it is evident that the two operations were undertaken under different conditions of weathering and erosion and were probably, therefore, separated by a significant period of time.

The limited Fourth Dynasty quarry face, identified by Lehner (Figure 3 and Plate 3i), was excavated from relatively durable Member I rocks. Since being quarried in the Fourth Dynasty, this quarry face has been subject to weathering and erosion (including the processes of chemical weathering and exfoliation) and yet exhibits only slight degradation (see Plate 3i). By contrast, the same Member I beds, exposed elsewhere within the Sphinx enclosure, are more intensely degraded. The contrast in the intensity of degradation at the western limit of the Fourth Dynasty quarrying is striking (Plate 4i)29, with the exposures beyond the limit of quarrying being heavily degraded.

I consider that the generally more intense degradation of the Member I rocks exposed within the Sphinx enclosure, can only be explained by attributing the construction of the Sphinx and the first phase of the Sphinx temple to a period before Khufu quarried the site, when the exposed limestone was subject to erosion by surface run-off.

During incorporation into Khafre's Fourth Dynasty mortuary complex, the Sphinx temple underwent a second phase of construction, during which modifications were made to the northern and southern walls of the temple, together with limited quarrying of the Member I limestones to the immediate north. As these modifications to the Sphinx temple took place after Khufu's quarrying of the plateau, the newly exposed Member I limestones were not subject to erosion by rainfall run-off and, therefore, do not show the same pattern of intense degradation that is apparent elsewhere within the Sphinx enclosure.


Site inspection has shown that for most of its length, Khafre's causeway runs along a ridge of exposed bedrock, with a masonry pavement present only towards the east. Bedrock exposed beneath this pavement, on the northern shoulder of the causeway, indicates that this masonry is only a single course thick and has been used simply to provide a constant gradient both along and perpendicular to the longitudinal axis of the causeway30.

The eastern end of the causeway runs along the top of the southern Sphinx exposure and, when viewed in plan, it can be seen that these two features share a common alignment (Figure 3). Experience suggests that such common alignments rarely develop by chance and this raises the possibility that the two features were constructed at the same time. It follows, therefore, that if the Sphinx pre-dates Khufu, the causeway must also have been constructed some time before Khufu's development of the site31.

Further support for this hypothesis is available from analysis of the spatial relationship between the causeway and the two quarries that were worked during Khufu's reign (Figure 2 - the northern quarry has been referred to earlier in this paper). With respect to the southern most of these quarries, Lehner states that "At the N, the floor of the quarry appears to slope up to the Khafre causeway..."32. Later, when discussing the northern quarry, "[the area] contained dumped debris which apparently fills an extensive quarry limited on the S by the Khafre causeway and on the east by the Sphinx depression."33

Under the conventional sequence of development, "Khafre's" causeway (and the Sphinx), were undeveloped at the time of Khufu's quarrying. If this sequence is correct, why should the extent of the quarrying have been limited by a feature (the causeway) that was not developed until sometime after Khufu's reign? The conventional sequence of development requires us to accept that Khufu's workmen went to the trouble of opening up a second quarry to the south of the causeway, rather than remove a linear body of rock which, at the time, served no apparent purpose.

The common alignment of the causeway and the southern Sphinx exposure indicates that, like the excavation of the Sphinx and the construction of the Sphinx temple, the alignment of "Khafre's" causeway was established some time before the construction of Khufu's mortuary complex. Under this revised sequence of development, interpretation of the spatial relationship between the causeway and Khufu's quarries becomes quite straightforward - with the causeway limiting the extent of the later quarrying works.


"Khafre's" causeway links the Sphinx and adjacent temples in the east, to Khafre's mortuary temple and pyramid in the west. During inspection of the site undertaken for this paper, a number of significant features of Khafre's mortuary temple were noted.

Firstly, this temple can be seen to consist of two distinct elements, characterised by different architectural styles (Figure 5). Aerial photographs34 show a clear dislocation between these two elements.

The remains of the western temple, closest to Khafre's pyramid, consist of low lying (typically one or two courses), moderately sized, well squared masonry and, when viewed in plan, a large proportion of the temple consists of open space. By contrast, the eastern end of the temple (approximately 40% of the total plan area), consists of large (cyclopean) masonry, each block being the equivalent of several courses high. When viewed in plan, a large proportion of this section of the temple consists of masonry, with relatively little open space. In many areas the masonry is severely degraded, with much of this degradation continuing across the exposed faces of adjoining blocks, suggesting that this degradation has developed with the masonry in-situ.

In addition to the distinct architectural styles of the temple, I have noted that the cyclopean portion of the mortuary temple appears to be constructed on an elevated site, with ground levels falling away sharply to the east and less steeply to the west, towards the foot of Khafre's pyramid (Plate 4ii). These observations have been confirmed by reference to survey drawings35 which show that ground levels in the vicinity of the mortuary temple (defined by spot heights taken outside the temple, close to the northern and southern walls) reach the most elevated point at the western limit of the cyclopean portion of the temple (see Figure 5)36.

On Figure 6, Khafre's mortuary complex is shown in plan37, together with a section, drawn to show both the existing and the original ground profiles. It can be seen from the section that, for an observer in the vicinity of the Sphinx, the western 'horizon' is formed by a break in slope at the eastern end of the cyclopean portion of the mortuary temple. This prominent location is also readily apparent on site - when viewed from the east, the elevated site of the cyclopean masonry obscures the base of Khafre's pyramid.

On the basis of the topography, the eastern portion of "Khafre's" mortuary temple (the Proto-mortuary temple) can be seen to enjoy a more prominent position than even Khafre's pyramid. This dominant position on the western 'horizon', the distinct, and ostensibly more primitive architectural style of the Proto-mortuary temple and its clear association with the causeway and consequently the Sphinx, suggests that the Proto-mortuary temple may also pre-date Khufu's development of the site.

This suggests that, as was the case at Saqqara where the earliest part of the necropolis was built on the edge of the escarpment overlooking the Nile valley, topography was one of the primary influences on the layout of the pre-Khufu structures at Giza. It follows, therefore, that the alignment of "Khafre's" causeway may have been established simply by directly connecting the prominent sites of the Sphinx and the Proto-mortuary temple.


The case presented above indicates that a number of structures within the Giza necropolis, including the Proto-mortuary temple, "Khafre's" causeway, the Sphinx and the Sphinx temple, pre-date Khufu's development of the site. Given the intensity of the degradation of the western Sphinx exposures, and the rate at which geological processes such as erosion operate, I consider that this construction took place not only before the reign of Khufu, but that it probably pre-dates the Fourth Dynasty.

Support for this conjecture may be provided by Lehner, who has undertaken a study of the masonry used to restore the Sphinx. Two types of restorative masonry have been identified, the oldest of which consists of large limestone blocks, up to 1m in length, which have been placed directly against the in-situ strata from which the Sphinx was carved. These larger blocks are overlain by a second layer of later, brick-sized limestone masonry.

Lehner initially considered that the earliest masonry was placed as part of the original (Fourth Dynasty) construction and was intended to make good any natural discontinuities in the limestone. To demonstrate this, the 1979/80 ARCE Sphinx Project, for which Lehner was Field Director, sought evidence for tool marks on the in-situ limestone underlying the large masonry. However, as Lehner states "...the profile of the core seems in all cases to be one of severe erosion, leaving the softer yellowish bands and harder intermediate strata showing a profile of successive rolls and undulations. These considerations would seem to indicate that the core-body of the Sphinx was already severely eroded when the earliest level of large-block masonry was added to it"28.

To reconcile these findings with the established Fourth Dynasty date of the Sphinx, Lehner has since attributed the earliest masonry to the Eighteenth Dynasty restoration undertaken by Thutmose IV38. The revised sequence of development proposed in this paper, however, makes it possible to reconcile the "severe erosion", identified by Lehner, with restoration which Hawass has more recently confirmed to be of Old Kingdom date15.

It is argued that for any pre-Fourth Dynasty structures to have been preserved from Khufu's extensive development, they must have had some religious or other significance - possibly forming part of a temple or cult complex. The evidence presented so far, however, can only provide the most general relative dating for the construction of this complex and, in order to provide a better resolution for these dates, reference has been made to the known use of stone in ancient Egyptian architecture.

The basis for this line of reasoning is that the culture that undertook the construction of the cult-complex at Giza, must have had the experience and have developed the ability to work stone masonry. The earliest known use of stone in ancient Egypt is from pre-Dynastic times (e.g. the Coptos statues39). Somewhat later, use of blocks of stone as architectural elements in tombs, is known from the First and Second Dynasty at Helwan40. It is understood that the Palermo Stone attributes construction in stone to the last pharaoh of the Second Dynasty, Khasekhemwy41, and this date is generally consistent with the earliest known stone masonry in Egypt - from the Gisr el-Mudir at Saqqara (provisionally dated to the mid- to late Second Dynasty42). This development in the use of stone in Ancient Egypt has, therefore, been used as a framework to establish the following sequence of development for the Giza necropolis:

    1) The Pre-Dynastic Period - the site may have achieved some local significance, with the principal focus of veneration being the prominent outlier from which the Sphinx was later to be carved. Perhaps resembling the head of a lion, this outlier faced east towards the rising sun and as such, may have been linked to sun-worship, justifying its own cult temple. This temple, either constructed from mudbrick or reeds, would have been erected in front of the outlier. A second temple, dedicated to the setting sun would have been constructed such that, when viewed from the Nile valley, it occupied a prominent position on a low knoll on the western horizon.

As Edwards states43, "In Egyptian mythology the lion often figures as the guardian of sacred places. How or when this conception first arose is not known but it probably dates back to remote antiquity. Like so many other primitive beliefs it was incorporated by the Priests of Heliopolis into their solar creed, the lion being considered the guardian of the gates of the underworld on the eastern and western horizons" (my italics).

2) Early Dynastic Period (Dynasties 1 to 3) - evidence of Giza's importance before the Fourth Dynasty is provided by a number of artefacts that have been recovered from areas to the south of the site. Emery44, makes reference to the discovery of a large but much destroyed royal monument, believed to be the tomb of the consort of Uadji, a First Dynasty king. Further evidence of Early Dynastic associations with Giza includes inscriptions on a flint bowl bearing the name of the first king of the Second Dynasty, Hotepsekhemui, and jar-sealings bearing the name of a later Second Dynasty king, Neteren. "Covington's Tomb" provides evidence of Giza's continued use into the Third Dynasty45.

The principle of a 'disconnected' head does not feature in Egyptian iconography, therefore, as the techniques of stone masonry and the theology of the solar cult developed, sometime in the later part of the Early Dynastic Period, the idea was established to liberate the body of the lion from the rock, leading to the carving of the Sphinx, possibly with the head of a lion46 and the construction in stone of temples to the rising sun (the Sphinx temple) and the setting sun (the Proto-mortuary temple).

The presence of the two temples can be seen to reflect one of the main tenets of ancient Egyptian theology - the principal of duality - which, with respect to the sun-god, manifested itself in the complimentary nature of the rising and the setting sun. It appears that the principal of duality was incorporated into the very architecture of the solar-cult complex (all italics are mine):

"In front of the Great Sphinx at Giza stands a temple of unique design [the Sphinx temple]....two German scholars [Ricke and Schott] have interpreted it thus: two cult niches on the east and west were for rituals dedicated to the rising and setting sun......."47

"At each end of the transverse section of the entrance hall [to Khafre's mortuary temple] a long and narrow chamber penetrated deeply into the masonry core of the building......Ricke, however, is inclined to regard these as having been built for models of the two solar barques of the sun god, the southern for the day barque and the northern for the night barque...."48.

The alignment between the Sphinx and the Proto-mortuary temple was established, perhaps as a processional or ceremonial route, connecting the elevated sites of the Sphinx and Proto-mortuary temple and running along the southern limit of the Sphinx enclosure.

3) Fourth Dynasty - when selecting the site for his mortuary complex, Khufu chose the site of the established solar-cult at Giza. This choice of location may well explain the name given to Khufu's pyramid by the ancient Egyptians, which has been translated as "The Pyramid which is the Place of Sunrise and Sunset"49, a name which accords with the significance of Giza suggested by my revised sequence of development.

By the reign of Khufu's successor, Djedfre, the name 'Re' had been incorporated into the royal cartouche. Certainly by the reign of Khafre, the principle of the Pharaoh as the earthly manifestation of the sun god had developed further. It was possibly in order to strengthen this association, that Khafre incorporated the existing solar-cult complex into his own mortuary complex50. In so doing, he built his own valley temple, modified the Sphinx temple, constructed a covered processional way along the existing causeway and incorporated the Proto-mortuary temple into his mortuary temple. He may also have been responsible for the Old Kingdom masonry placed on the body of the Sphinx and for re-carving the Sphinx's head into that of a human form (although work by police forensic artists has shown that this was not undertaken to produce a likeness of Khafre51).

The few hundred years available under my revised sequence of development is considerably less than the thousands of years allowed by Schoch for the development of the more intense degradation in the west of the Sphinx enclosure. I consider, however, that given the relatively weak nature of the Upper Mokattam Limestones and the particular conditions of weathering and erosion that prevailed during this time, it is entirely conceivable that this more intense degradation could have developed within such reduced timescales.

Although predominantly arid conditions were experienced throughout the Early Dynastic Period and Old Kingdom, conditions were generally not as arid as those that exist at present. Under these less arid conditions, unlike the weathering processes described by Gauri et al, chemical weathering is likely to have resulted in the leaching of soluble salts from the exposed limestones. As this soluble component was removed from the rocks, the potential for further chemical weathering is likely to have been reduced.

For those exposures which were not subject to erosion by rainfall run-off, the mantle of weathered rock that developed as a result of this leaching process will have remained in-situ. In the west of the Sphinx enclosure, however, erosion from run-off during heavy seasonal rainfall, will have removed much of the weathered limestone, exposing the comparatively unweathered strata from beneath. Given the significant soluble component of these newly exposed rocks, it follows that the effect of this seasonal erosion will have been to promote renewed phases of chemical weathering and leaching, thereby accelerating the degradation process.

I consider that under these particularly aggressive conditions of weathering and repeated erosion, degradation of the western Sphinx exposures could have developed over a period of time which, in geological terms, was relatively short.


A number of authors have made reference to a ditch which reportedly runs parallel to "Khafre's" causeway and enters the Sphinx enclosure in the south west corner. Currently, only a short stretch of the eastern end of this ditch is exposed and the only evidence for the continuation of the ditch beyond this point, is a slight depression in the accumulated sand. Although this depression can possibly be identified on the 1:5000 scale topographic maps of the site37, running parallel with the causeway, it appears to extend no more than 35m from the Sphinx enclosure.

There is no consensus on the function of the ditch, it being variously described as a drainage ditch27 and a boundary marker49. To support the established sequence of development for the site, a number of Egyptologists refer to this ditch as a drainage feature and argue that it indicates that the Sphinx was excavated after the ditch was cut, as the ancient Egyptians would not deliberately have discharged run-off into the Sphinx enclosure.

However, when the surface hydrology of the area is considered (under the conventional sequence of development) the drainage function of the ditch has to be questioned. The quarrying undertaken by Khufu and Khafre (Figure 2) would limit the available catchment to the north of the ditch. To the south, the only area from which rainwater could be shed is from the roof of the causeway structure. If we assume that Khafre's causeway resembled that of Unas, a central light-slot would have resulted in the need for a second drainage ditch on the southern side of the causeway. The published literature makes no reference to such a second ditch and none is apparent from site inspection.

The only other obvious catchment for the drainage ditch is the area within Khafre's pyramid court and around the mortuary temple. However, any run-off from these areas could have been discharged into the western end of the nearby quarries, rather than carried all the way to the Sphinx enclosure.

Given these reservations regarding the drainage function of any ditch at this location, I have investigated its other proposed function - that of a boundary marker. As stated above, available published information has been unable to confirm that the ditch runs the full length of Khafre's causeway. The only location at which inspection of the flank of the causeway is currently possible is at a point, approximately halfway along, where an underpass has been cut through the limestone. Although the accumulated sand has been removed from this location, inspection undertaken in May 1998 and July 1999 failed to establish any evidence for the continuation of the ditch up to or beyond this point.

Given the uncertainties surrounding the purpose and the true extent of this ditch, I consider that without further investigation, it has limited value in support of any argument for the sequence of development of Khafre's mortuary complex.


It is generally considered that extensive development at Giza was limited to the Fourth Dynasty and what little activity there was before this, was restricted to areas to the south of the necropolis (see item 2, page 10). Although my argument for an Early Dynastic solar-cult complex, with the Sphinx at its focus, clearly runs contrary to this general opinion, there is published archaeological evidence to indicate activity within the Giza necropolis from as early as the late Predynastic period.

Mortensen52 discusses four ceramic jars, reportedly found in the late 1800's "at the foot of the Great Pyramid" (the exact location has not been recorded). When these jars were first found, the Predynastic period of Ancient Egyptian history was little understood and, given the accepted Fourth Dynasty context of the Giza site, the jars were assumed to be of the Fourth Dynasty. Mortensen, however, has re-assessed these jars and considers them to be typical of the late Predynastic Maadi period. Given that the jars were found intact, Mortensen has also argued that they were from a burial rather than a settlement site.

The survival of pre-Fourth Dynasty artefacts within the Giza necropolis has to be considered in the context of the Fourth Dynasty development. Figure 7 shows, in general terms, the Fourth Dynasty land-use of the site, illustrating that most of the available area within the necropolis was either quarried or built upon. These are both rather destructive activities which may have necessitated the removal of earlier structures and the disposal of the resulting 'site clearance' debris. This debris may have been deposited in the base of worked-out quarries or in other known areas of dumping, outside the area of construction.

In the mid 1970's an Austrian Egyptologist, Karl Kromer, investigated one such area of debris, some 1km south of the Great Pyramid (Figure 7). Within the fill, Kromer reported finds from the Late Predynastic, the First, Second and Fourth Dynasties53.

Kromer's work has been criticised by Butzer54, however, analysis of this critique shows that Butzer did not question the age of the finds but concentrated on Kromer's interpretation, suggesting that the stratigraphy of the excavation site was more complex than Kromer had reported. Whereas Kromer identified the deposition of only a single 'settlement', Butzer suggested that a number of such episodes were represented, the remains of which were separated by layers of wind-blown sand and possible debris slides. Butzer did accept, however, that the deposits excavated by Kromer consisted of accumulations of drift-sand together with the remains of development which had been removed from the area of the pyramids and dumped at the excavation site during the Old Kingdom.

Although Butzer did not criticise the age attributed to the finds, Kromer's interpretation has been criticised by others. Whilst the age of ceramics, stone tools etc. may remain contentious, most people do accept the jar sealings that were excavated as being Early Dynastic55.

When faced with claims that the Sphinx is older than is generally accepted, Egyptologists frequently cite the "Fourth Dynasty context" of Giza, claiming that there is little, if any evidence for activity at the site before this time. Although most of the pre-Fourth Dynasty artefacts found at Giza have been recovered from outside the Fourth Dynasty necropolis, it can be argued that the mechanism by which this earlier material was removed from its original position and deposited elsewhere, is widely understood and generally accepted.

The work of both Mortensen and Kromer has demonstrated, therefore, that there is evidence for pre-Fourth Dynasty activity at Giza. What is noteworthy is that the period of time indicated by this evidence is consistent with the timescales that I have established on the basis of other quite independent considerations (such as the use of stone masonry in Ancient Egypt).


When considered in terms of the hydrology of the site, the distribution of degradation within the Sphinx enclosure indicates that the excavation of the Sphinx and the original construction of the Sphinx temple, pre-date Khufu's early Fourth Dynasty development at Giza. The spatial relationships between "Khafre's" causeway, the Sphinx and Khufu's quarries provides additional evidence that the causeway and the Sphinx were constructed some time before Khufu's quarrying began. The prominent location and close association of the Proto-mortuary temple with the causeway indicates that this structure may have also formed part of the early development of the site.

On the basis of the intensity of erosion present along the western Sphinx exposures and the known use of stone in ancient Egyptian architecture, a case can be made for the development of the site which parallels the development of sun worship in ancient Egypt. The excavation of the Sphinx and the construction in stone of the other elements of this solar-cult complex are, therefore, tentatively placed sometime in the latter half of the Early Dynastic Period.

As an established cult centre, the site was selected by Khufu in the early Fourth Dynasty, for the construction of his pyramid complex. Later in the Fourth Dynasty, the Solar-Cult complex itself was adopted by Khafre as he developed, not only his mortuary complex, but also the association of the king with the sun god, Re - the principal state god of the time. During the continued Fourth Dynasty development, which lasted until after the reign of Menkaure, cultural material associated with earlier activity, was removed from the areas of construction and deposited in areas such as that investigated by Kromer, to the south of the site.

The origins of the Sphinx as an icon are unclear. On the basis of the sequence of development that I propose, I consider that the concept of the man-headed lion was an evolutionary one, originating in the Early Dynastic association of the lion with solar worship43 and culminating in the Fourth Dynasty association of the Pharaoh with the sun-god - an association made manifest by re-carving the head of the Great Sphinx in the form of the divine king, perhaps during the reign of Khafre.

It is interesting to speculate whether, given the monumental proportions of the Great Sphinx and its undoubted influence on contemporary culture, the Giza Sphinx may have been the inspiration for all later Sphinxes. Such a hypothesis would certainly explain the lack of such votive objects that are known from the period before Khafre.

In his work, "In the Shadow of the Pyramids", Malek offers a degree of confirmation of my revised sequence of development: "It seems that the official dogma concerning the king's relationship with the gods was re-defined and systematized during the Fourth Dynasty in order to make him part of a system with the creator sun-god Re.... The rise in importance of the sun-god lead to his recognition as the main state-god of the Old Kingdom, and the appearance of the name of the god in royal names and titles reflected it."

The unprecedented and unrepeated inclusion of additional elements (the Sphinx and Sphinx temple) in the mortuary complex of Khafre and the use of the hieroglyphic symbols for "to rise" and "Re" (the rise of Re?) in the royal name, supports the assertion that it was Khafre who achieved this "re-definition" of the king's relationship with the gods. How better could the association of the king with the sun-god have been symbolised, than by linking Khafre's "mansion of eternity" with a long established site of solar worship and the everlasting circle of birth, death and re-birth manifested by the daily rising and setting of the sun?

About the Author

Colin Reader has an honours degree in Geological Engineering from London University. Within this discipline, which links civil engineering with geology, he has considerable professional experience in the study of the historic development of sites - work undertaken from both field and desk-based research. He has a long standing interest in ancient Egypt, but a specific interest in the Giza plateau, which he has visited on a number of occasions and researched at length. Recently, Colin travelled to Cairo with the BBC to take part in the filming of the ideas set out in this paper. Contributions to the documentary, which is to be shown on the 'Discovery Channel' sometime in the year 2000, were made by Dr Zahi Hawass and Dr Robert Schoch.



1.   R.M. Schoch, "Redating the Great Sphinx of Giza", KMT Vol 3 No. 2, (1992) p53-59 & p66-70.

2.   J. Baines and J. Malek, "Atlas of Ancient Egypt", p36. For consistency all dates used in this paper have been taken from this reference.

3.   J.A. Harrell, "The Sphinx Controversy - Another Look at the Geological Evidence", KMT Vol 5 No. 2 (1994), p70-74.

4.   K.L. Gauri, J.J. Sinai & J.K. Bandyopadhyay, "Geologic Weathering and its Implications on the Age of the Sphinx", Geoarchaeology Vol 10, No 2 (1995), p 119-133.

5.   In his paper (note 3), Harrell describes two processes to explain the wetting of sand accumulations within the Sphinx enclosure. Firstly, Harrell describes storm water run-off discharging across the plateau and into the accumulated sand. As discussed in more detail later in the text, the existence of large quarries upslope from the Sphinx would prevent such discharges. Secondly, Harrell considers that extreme Nile inundation was capable of introducing water into the lower lying sand within the Sphinx enclosure. He then relies on capillary action to carry this water up to 2m into the overlying sand. Although in hot, arid areas capillary fringes are present above groundwater in bedrock, I have to question whether any significant capillary fringe would develop in a loose, coarse grained soil, such as accumulated sand. In soil mechanics, capillarity is modelled using the concept of soil suction and is governed by particle size and the size and content of any interparticle voids. G.N. Smith states "For sands and gravels above ground water level suction effects are fairly negligible" (from "Elements of Soil Mechanics", 5th Ed.1982, p434).

6.   K.L. Gauri - "Geologic Study of the Sphinx", Newsletter of the American Research Centre In Egypt, 127 (1984), p24-43.

7.   K.L. Gauri - "Deterioration of the Stone of the Great Sphinx", Newsletter of the American Research Centre In Egypt, 114 (1981), p35-47.

8.   A.N. Choudhory et al, "Weathering of Limestone Beds at the Great Sphinx", Environmental Geology and Water Science, 15, (1990), p217-223.

9.   For a discussion of the disposition of quarries within and adjacent to the Giza necropolis see M. Lehner, "The Development of the Giza Necropolis - The Khufu Project", Mitteilungen des Deutschen Archaologischen Instituts Abteilung Kairo, 41, (1985)

10. F. El-Baz, "Desert builders knew a good thing when they saw it.", Smithsonian, April 1981, p 16-121.

11. M.M. el-Aref and E. Refai, "Paleokarst processes in the Eocene limestones of the Pyramids Plateau, Egypt", Journal of African Earth Sciences, Vol 6 No. 3, p367-377.

12. T. Aigner, "A Pliocene Cliff Line Around the Giza Pyramids Plateau, Egypt.", Palaeogeography, Palaeoclimatology, Palaeoecology, 42 (1983) p313-322.

13. M. Lehner, "The development of the Giza Necropolis: The Khufu project", Mitteilungen des Deutschen Archaologischen Instituts Abteilung Kairo, 41, (1985), Figure 3A, item 14.

14. The tomb of Kausert, for example (Porter and Moss, Volume III, Memphis, 2nd Edition 1994, p286 and plan XXIII, grid D-10), is partly rock cut (much of the original masonry superstructure is now missing), however, the upper rock surface of this tomb preserves the original slope of the ground. That the original ground levels in this part of the site rise towards the north is confirmed by Lehner in his paper "Notes and photographs on the West-Schoch Sphinx Hypothesis" (KMT, Vol 5 No. 3 (1994), p40-48.) "....from the south wall of the Sphinx ditch and down the slope away from the ditch to the south behind the Valley Temple [of Khafre] ....". Here Lehner is referring to the topography to the south of the Sphinx, describing how the ground at this location falls away towards the Main Wadi in the south.

15. Z. Hawass, "Abstract for the First International Symposium on the Great Sphinx", Egyptian Antiquities Organisation, Cairo, 1992. "It seems that the Sphinx underwent restoration during the Old Kingdom because the analysis of samples found on the right rear leg proved to be of Old Kingdom date."

16. M. Lehner, "Notes and photographs on the West-Schoch Sphinx Hypothesis", KMT, Vol 5 No. 3 (1994), p40-48.

17. In their paper "Geologic Weathering and its Implications on the Age of the Sphinx" (see note 4), Gauri et al state "the vertical profiles of the strata of the Sphinx on all four sides as well as those on the south and west walls of the enclosure are rounded and exactly similar."

18. The alignments shown on Figure 3 represent only a selection of the most significant sub-vertical degradation features. There are a large number of additional exposed joints which, for clarity, are not shown - see Figures. 4c and 4d.

19. Courtesy of Robert Partridge and The Ancient Egypt Picture Library.

20. The aspect of a particular exposure (whether it faces north, south etc.) may result in a variation in the intensity of chemical weathering from one adjacent face to another. Aspect, however, does not appear to be a factor responsible for the distribution of degradation across the strata exposed at the Sphinx. For example, although of the same aspect, the western enclosure wall and the chest of the Sphinx show significant variations in both the nature and the intensity of the degradation present. Likewise, the north facing rump of the Sphinx is generally free from sub-vertical degradation features, unlike the similarly oriented western end of the southern exposure.

21. K. W. Butzer, "Environment and Archaeology: An Ecological Approach to Prehistory", Chicago, 1971. "....extensive sheet washing - in the wake of sporadic but heavy and protracted rains - are indicated ca. 4000 - 3000BC. Historical and archaeological documents suggest that the desert wadi vegetation of northern and eastern Egypt was more abundant as late as 2350 BC, when the prevailing aridity was established."

22. G.A. Reisner, "Mycerinus, the temples of the Third Pyramid at Giza", Chicago, (1931). The evidence for flood damage to the Valley Temple is described. In reconstructing the conditions that contributed to this damage, Reisner suggests that the natural hydrology of the site was interrupted by Menkaure's causeway. Run-off from the plateau in the north west, flowed along the northern edge of the causeway and was directed at the western walls of the Valley Temple.

23. M. Lehner, "The development of the Giza Necropolis: The Khufu project", Mitteilungen des Deutschen Archaologischen Instituts Abteilung Kairo, 41, (1985), Figure 3B, item 24.

24. A.A. Saleh, "Excavations around Mycerinus Pyramid Complex", Mitteilungen des Deutschen Archaologischen Instituts Abteilung Kairo, 30, (1974), p137

25. The limited area between the eastern limit of quarrying and the Sphinx enclosure may have generated a small volume of run-off during wetter periods. However, the erosive potential of this run-off is likely to have been minimal. For the more intense erosion of the western Sphinx exposures to be attributable to run-off from such a limited catchment, repeated storm events over a considerable period of time would be required. It is considered that such conditions are not available under the conventional chronology.

26. M. Lehner, "A Contextual Approach to the Giza Pyramids", Archiv fur Orientforschung, 32 (1985), p136-158.

27. M. Lehner and Z. Hawass, "Archaeology ", September/October 1994, p32-47.

28. Lehner, Allen and Gauri, "The ARCE Sphinx Project - A Preliminary Report", Newsletter of the American Research Center In Egypt, 112 (1980) , p3-33.

29. The western limit of the Fourth Dynasty quarrying can be seen in the middle foreground of Plate 4i, just beyond the reconstructed Amenhotep temple (see also Figure 3 and compare with Plate 3i).

30. V. Maragioglio and C. Rinaldi (1965), L'Architettura delle piramidi Menfite, part V. Survey drawings of the causeway support the observations made on site, that the masonry along the eastern end of the causeway is only a single course thick. Further, an underpass has been cut through Khafre's causeway. As these survey drawings and site inspection show, this underpass is cut through in-situ rock.

31. An alternative explanation for this common alignment is that it may have been achieved by 'trimming back' the southern exposure during a second phase of excavation within the Sphinx enclosure. Such a subsequent phase of excavation, however, is likely to be readily identifiable by the presence of comparatively 'fresh' cut faces along and adjacent to the southern exposure. Examination has established that no such 'fresh' exposures are present and it has, therefore, been concluded that the common alignment results from the Sphinx and causeway being constructed at approximately the same time.

32. M. Lehner, "The development of the Giza Necropolis: The Khufu project", Mitteilungen des Deutschen Archaologischen Instituts Abteilung Kairo, 41, (1985), p110-143.

33. Ibid. Although Lehner considers the western portion of this northern quarry to have been worked during the reign of Khafre, he acknowledges that the quarry was worked, in the east, under Khufu. It is the presence of this quarry that is considered to have brought an effective end to the erosion of the Sphinx enclosure by rainfall run-off.

34. M. Bridges, "Egypt: Antiquities from Above", p19 and 23.

35. V. Maragioglio and C. Rinaldi (1965), L'Architettura delle piramidi Menfite, part V.

36. Evidence that the ground profile at the site of the western portion of the Mortuary temple represents the natural topography of the site has been provided, by Lehner. In "The development of the Giza Necropolis: The Khufu project", Mitteilungen des Deutschen Archaologischen Instituts Abteilung Kairo, 41, (1985), Figure 3A, Lehner has reconstructed the topography of the plateau prior to any Fourth Dynasty development. On this reconstruction, the elevated site of the cyclopean portion of the mortuary temple is shown as a naturally occurring low knoll (between points 2 and 5 on the Figure). On subsequent drawings the edge of this knoll is shown as the western limit of quarrying (to the immediate left of item 11 - Figure 3B). In a separate paper "Some observations on the Layout of the Khufu and Khafre Pyramids", Journal of the American Research Center in Egypt , 20 (1983), p7-25, Lehner discusses the likely means by which the Khufu and Khafre pyramids were set out and levelled. Slightly different methods were used for each pyramid, however, in the case of Khafre's pyramid, the levelled area extended only some 16m from the foot of the pyramid casing. It can be determined from this that the levelling of the pyramid would not influence the topography at the eastern end of the mortuary temple.

37. Arab Republic of Egypt, Ministry of Housing and Reconstruction, Topographic sheets, F17 and F18, 1:5000.

38. M. Lehner, "The Complete Pyramids", 1997, p128-129 provides a profile of the Sphinx showing a distribution of the various phases of masonry.

39. Personal correspondence between the author and B.J. Kemp, 24 June 1997.

40. W. Wood, "The Archaic Stone Temples at Helwan", Journal of Egyptian Archaeology, 73, p59-70.

41. Mathieson et al, "The NMS Saqqara Survey Project 1993-1995", Journal of Egyptian Archaeology, 83, 1997, p17-54.

42. Personal correspondence between the author and Mr. I. Mathieson, Director of the National Museums of Scotland Saqqara Project, 15 July 1997.             

43. I.E.S. Edwards, "The Pyramids of Egypt", p122.

44. W. B. Emery, "Archaic Egypt", p73, 92 and 94.

45. W.M.F. Petrie, "Gizeh and Rifeh", London (1907).

46. The iconography of the recumbent lion is attested, for this period, by sculpture recovered from the First and Second Dynasty necropolis at Helwan - see "The Excavations at Helwan", Z.Y. Saad, Plate 49.

47. B.J. Kemp, Ancient Egypt: Anatomy of a Civilisation, p4.

48. I.E.S. Edwards, "The Pyramids of Egypt", p130.

49. P. Jordan, "Riddles of the Sphinx", 1998, p1.

50. It is the departure from construction at Giza, during the reign of Djedfre and during the reign of Khafre's little known successor, Baufre, that I consider severely undermines any proposition that the layout of Giza was established as a 'masterplan' at the time of Khufu.

51. J.A. West, "Serpent in the Sky", Revised edition, p230-232. Stadelmann has recently attributed the excavation of the Sphinx to the reign of Khufu, principally on the basis of facial features and the iconography of the nemes head-dress (see 'Royal Tombs from the Age of the Pyramids', R. Stadelmann in "Egypt - the World of the Pharaohs", R. Schulz and M. Seidel - Eds). Although this is not consistent with the geological evidence for the age of the Sphinx, it is interesting, that Stadelmann presents a challenge to the established association of the Sphinx with Khafre.

52. B. Mortensen, "Four Jars From the Maadi Culture found at Giza", Mitteilungen des Deutschen Archaologischen Instituts Abteilung Kairo, 41, (1985), p 145 to 147.

53. K. Kromer, "Siedlungsfunde Aus Dem Fruhen Alten Reich in Giseh". Osterreichische Ausgrabungen 1971 -75, Osterreichische Akademie Der Wissenschaften Philosophisch-Historische Klasse Denkschriften, 136

54. K.W. Butzer, Review of "Siedlungsfunde Aus Dem Fruhen Alten Reich in Giseh", Journal of Near Eastern Studies, Vol 41, no 2, April 1982, p 93-95.

55. Personal correspondence between the author and Dr. R. Friedman, 26 June 1999.