Two enigmatic circular mud brick structures in the Western Field at Giza
Stephen R. Phillips
I. Introduction
The Cairo University-Brown University Expedition returned to the Abu-Bakr Cemetery complex in the Western Field at Giza for its fourth season of fieldworkbetween January 2 and February 4, 2004.
To date, the project has expanded considerably our knowledge of the archaeological plan of the northwest area Giza plateau, first mapped by Lepsius in the early 1840’s. The project’s four seasons of fieldwork have produced over 13,000 survey points (pFig1), representing approximately 65% of the visible structures on
this roughly 380 × 220 m site occupying the far northwest section of the Western Field (pFig2). Three tombs numbered originally by Lepsius, Ipi (LG-19), and Persen and Irukaukhufu (LG-20 & 21, respectively), then excavated by Prof. Dr. AbdelMoneim Abu-Bakr, and presently undergoing re-clearing, mapping, and recording by the current project, together form a dominating tomb complex occupying the southwest portion of the Expedition’s survey area (pFig3, 4).

Although the archaeological and epigraphic analysis of this complex and its relationship to the history of the site as a whole is ongoing, an enigmatic, and perhaps unique, pair of circular mud brick and limestone block structures were re-cleared in 2004, prompting this preliminary report.
II. Site history
Working from east to west, employing at times some 200 workers, half of whom were quftis, Prof. Dr. Abu-Bakr excavated this roughly eight-acre site from the late 1940’s to the 1970’s. While a firmer dating of the site is a mission of the present project, preliminary analysis of architecture, iconography, and pottery seem to support working dates of the Fifth – early Sixth Dynasty for this portion of the Western Field.
Prof. Dr. Abu-Bakr was able to publish only a portion of his excavations prior to his death in 1976.
Since the close of his excavations, conservation work to preserve and protect the decorated mastabas and rock-cut tombs continued, and continues today, under the auspices of the Supreme Council of Antiquities. Part of the mission of the Cairo University-Brown University Expedition is to record the scenes and inscriptions in the tombs that Prof. Abu-Bakr found and the relief blocks from these tombs stored in the Cairo University magazine at Giza.
Prof. Dr. Abu-Bakr also made what may be a unique architectural discovery, a pair of circular, perhaps domed, mud brick and hewn limestone block structures built directly against the south wall of the limestone block mastaba of Ipi (LG-19). Except for a brief mention in the archaeological literature, it has received no attention.
Prof. Dr. Abu-Bakr provided a sketch (pFig5), briefly described the two structures, and identified them as ‘cage du hyène’ based upon his interpretation of their form vis-à-vis the depiction of hyenas as funerary offerings, for example, in the nearby mortuary chapel of Persen (LG-20, 21) as well as elsewhere at Giza.
In 2004, the Expedition re-cleared these two structures for the purpose of survey and initial archaeological analysis (map1). If the work begun in 2004 and that of upcoming seasons should support Prof. Dr. Abu-Bakr’s suggestion identifying these structures as ‘hyena cages’, they would be the first, and to this point the only, known examples of such a kind in ancient Egypt.
III. Description of the ‘Cage du Hyène’ structures
The two circular structures are constructed of unbaked mud bricks and hewn limestone blocks (pFig6). They stand side-by-side, each essentially a mirror image of the other, directly against the south wall of the limestone mastaba of Ipi (LG-19). The easternmost structure is the best preserved of the two. The westernmost, being more exposed to west-to-east wind and weather degradation, is in the worst state of preservation, having lost nearly all of its western and northern sides. Each structure has two ‘accesses’, built of hewn limestone blocks forming floored passageways, and they appear to have had originally, roofs, based upon surviving blocks (pFig7,8). While each structure is a mirror image of the other and nearly identical, there are differences in construction, perhaps reflecting different construction times and/or uses. For recording purposes, the two structures have been designated as ABC–69a (the easternmost) and ABC-69b (the westernmost).
Structure ABC-69a
ABC-69a is centered on the mid-line of the south wall of the mastaba of Ipi (LG-19). It is constructed of sun dried mud brick walls, averaging 90 cm thick, with what may be an interior flooring of limestone paving stones, set upon the ground. The interior diameter of the structure, while not perfectly round, is about 290 cm. The surviving northern wall segment, that portion directly against the south wall of
the mastaba of Ipi, retains a height of about 110 cm, or five courses of mud brick, apparently deflated one course from the time of Prof. Dr. Abu-Bakr’s sketch (pFig5). Brick size is quite large, averaging 60 cm long, 30 cm wide and 20 cm thick. The eastern, western and southern walls are eroded down to only one or two courses in most places. The walls are constructed in a manner consisting of one brick laid in a circular arrangement to form the enclosure with another row of bricks abutting the sides of the circular-oriented bricks. Thus, the thickness of the walls equals one width and one length of brick size. The brick bond here appears to correspond to the CX1 brick bond of the corpus set forth by Dr. A. J. Spencer (Brick Architecture, 137 and pl. 20, see also 135–139). The circular arrangement of the bricks naturally created wedge-shaped joints between the bricks, such as those found in vaulting. These joints were filled, mostly on the exterior courses, by mud brick of the same thickness as the other bricks that had probably been cut-down to, or were perhaps made specifically as, wedge shapes sized to fill the gap they were intended to fill. Additional joint-filling material, including where the two structures converge at the wall of Ipi (LG-19, pFig9), consists of mud, sand, and/or desert gravels. No evidence survives to indicate whether or not the interior or exterior walls were once plastered.
Although both structures are now open to the sky, it is possible that the two perhaps had domes or vaulting originally. Surviving walls in both structures appear to rise vertically for the first two courses, above which is an inward-pitch. We used a Johnson Angle Locater® inside structure ABC-69b, and recorded an inward-pitch (cf., pFig5) of 15° on a section of the third-course bricks on its eastern wall. The state of preservation of both structures prevents us from concluding definitively that domes did exist at their tops. The angle measurements we obtained imply that such was perhaps the case. In general, however, domed architecture in ancient Egypt was not common, nor was fully circular architecture.
Structure ABC-69a was filled with a 65 cm layer of deflated mud brick, loose soil backfill and wind-blown sand. Re-clearing was conducted which included the retention of both sifted and un-sifted soil samples for later analysis, and the retention of flora and faunal remains. At the southwest side in the structure a basin
with a channel passing through the wall into the interior was exposed (pFig9, 10), consisting of a single block of carved, white limestone measuring about 42 × 36 cm at the base, 31 × 31 cm at the top and 23 cm in height. The basin hollowed into the top of this block measures some 30 × 26 cm at the top, 26 × 21 cm at the bottom, and is about 10 cm deep. Richard Cook estimates its liquid capacity at about 5–6 liters.
The sketch of this structure drawn by Prof. Dr. Abu Bakr (pFig5) depicts what appears to be a nearly identical feature passing through the southwest wall of structure ABC-69a, in a position that would place it in a direct line with the basin feature (not visible in his sketch) on the inside. At the bottom of the interior, an approximately 5–10 cm thick ‘living floor’ layer of hard-packed mud was exposed. Test cleaning of an area of this layer was undertaken just inside the structure at the entrance to the south-oriented limestone block passageway. A 70 × 30 cm section of this single layer of hard-packed orange- brown sandy soil mixture was cleared until the uppersurface of a limestone block was exposed at a depth of about 8 cm The edges of two more laid-in limestone blocks were also revealed likely indicating the interior has a complete floor. This will be corroborated when re-clearing is recommenced next season. An incomplete mammalian skeleton was partially revealed in situ embedded in this layer, lying against the base of the limestone basin. Regrettably, the cranium is not extant. Additional animal bones, some of which bear forensic signs of carnivorous gnawing, as well as at least one carnassial tooth, were recovered,
or partly uncovered, throughout the interior of the structure at or near the lowest levels of the fill deposit, as well as at or within the ‘living floor’ layer. Again, these finds were made at the end of the season; so that proper zooarchaeological and archaeological analyses can be carried out, the skeleton and additional embedded remains in the lowest layer, the hard-packed ‘living floor’, were covered, re-buried, and left in situ for further investigation beginning with the next season, while the recovered soil and faunal samples were placed in storage.
Entrance and egress for both structures was gained through the limestone block passageways (pFig5-9). Structure ABC-69a, like its counterpart, has two such features, one long (oriented southeastward), and one short (oriented due south). The surviving portion of the longer southeastern passageway measures approximately 310 cm in length, 50 cm in interior width, and from 50 cm in height closest to the structure, the proximal end, to some 60 cm high at its furthest, distal, point from the structure. The variation in heights is perhaps due to erosion of the limestone. The surviving limestone blocks forming the sidewalls measure between 90–110 cm long, by 50–60 cm high, by 19–20 cm thick. Blocks of similar shape and size were installed on the surface, creating flooring, with the upright blocks set upon them. The eastern wall of the passageway now seems to sit out of position, off the flooring. Whether or not this was a deliberate construction feature or the result of lateral movement over time is unclear. The two upright blocks at the distal end of the passageway, shown in pFig5, are now lying horizontally, having fallen or were moved since the sketch was drawn. The sketch seems to show them in a position to serve as blocking stones at the distal end of the passageway. The last two wall blocks have 13 cm wide notches apparently cut into their upper edges (visible in pFig3, upper right, also pFig9).

Whether or not these notches are a construction feature, and thus may have functioned in some way with a door or a portcullis, or perhaps as support for a beam to support a roof block, or are simply artifacts in blocks reused from another location, is unclear. The blocks appear to be in situ, although the notches are no longer exactly opposite one another, being now some 35 cm off-center. The shifting of the eastern sidewall of the passage from the flooring, however, may be a factor. At the proximal end of the passageway, nearer the structure itself, slots have been cut into each side of the interior wall surface and into the floor slab underneath them, all three of which still align perfectly, forming a contiguous slot, adding to the evidence that this passageway may have once contained at least one, and most likely two or more sliding ‘doors’ or portcullises (see pFig8, center, for a similar slot in the easternmost wall block of the shorter, south-oriented, passageway). Roofing blocks no longer survive over this passageway, although two are shown in situ and one is shown fallen down in Prof. Abu-Bakr’s sketch (pFig5). At this time, it is unclear how, or if, they might have been arranged once to accommodate functional, or non-functional, sliding doors or portcullises.
The second, shorter, south-oriented, centrally located passageway is constructed in a similar manner. It measures some 110 cm in length (just longer than the thickness of the mud brick wall itself), about 60 cm in interior width, and has only two blocks extant that form the sidewalls, the easternmost measuring about 105 cm long, 55 cm  high, and 15 cm thick, while the westernmost is about 120 cm long, 55 cm high, and 15 cm thick. Once again, these blocks are set upon limestone flooring blocks. This passageway, too, has slots carved into the interior side of wall blocks, at the end of the passageway away from the structure (visible in pFig8,9), adding to the evidence that both passageways once contained doors or portcullises. The flooring slabs are deteriorated badly and do not retain corresponding slots. This passageway is the only one of the four passageways that still retains one of its roofing blocks in situ (visible in pFig8, center, also pFig9), measuring 90 cm long, 60 cm wide, by 15 cm thick. Measurements taken on other detached blocks associated with ABC-69a & b indicate that at least one, found leaning just inside the entrance to the longer passageway of ABC-69b, and perhaps others, once was a roof block. Whether or not this passageway, like its counterpart in structure ABC-69b, was ever longer than it is now, most likely cannot be determined given the present deflated state of the site.
Structure ABC-69b
ABC-69b is situated against the western side of structure ABC-69a, and likewise directly against the south wall of Ipi (LG-19) (pFig3,4,6,9). As mentioned earlier, it is badly deteriorated on its northern and western sides, and badly deflated on its southern side. It is essentially a mirror image of ABC-69b, yet it does differ. For instance, its interior is more elliptical, measuring some 230 cm on its north-south axis. Structure ABC-69b is constructed on the deeper bedrock surface; the elevation of the wall base here is some 55 cm lower than that of ABC-69a (see elevation view, pFig9), vis-à-vis ABC-69a, which appears to have been built upon the hard-packed sandy soil surface overlying the bedrock. Whether this was a result of deliberate site preparation at the time of the original construction or a result of adapting the structure to natural topography at the site is under investigation. The mud brick wall on the eastern side of ABC-69b survives to a height of some 120 cm on the eastern side, where pitch angle measurements were obtained. Brick size varies somewhat, with some bricks measuring the same 60 × 30 × 20 cm as those in ABC-69a, and others being even larger, around 60 × 40 × 30 cm. It is tempting to argue this could perhaps indicate different dates of construction, or different sources of mud bricks, or their reuse from elsewhere; however, such suggestions must be approached with caution. The juncture of the east wall of ABC-69b with the west wall of ABC-69a (pFig9), with the latter built against the former with a fill of sand and stones packing the northern triangularly shaped joint thus created between the two, argues that ABC-69b was probably at least completed first. The construction technique and brick pattern of the walls in this structure is the same as that in ABC-69a, and it was here, as noted, where pitch angle measurements were obtained.

Wall thickness, at about 90 cm, is the same as structure ABC-69a. The walls, however, differ from those in ABC-69a in an important respect: they are built upon a foundation ring of hewn limestone blocks, whose thickness ranges from 25–30 cm (see pFig9). These blocks in turn rest upon bedrock, which here is sloping towards the south. To level the blocks, and thus the walls, a layer of what is now hardened, dark brown, sandy tafl was applied between the blocks and the bedrock.
Like its counterpart, structure ABC-69b was filled with a 65–75 cm layer of loose soil backfill and wind-blown sand, which, given the difference in its floor depth, equaled just above surface level. Again, re-clearing was undertaken until the surface levels were exposed. No artifacts, flora, or faunal remains, were found in the fill or elsewhere in the structure. Unlike ABC-69a, which appears to have a limestone block floor, ABC-69b has a natural floor. Unlike ABC-69a, however, this floor has an irregular oblong cavity sunk into its northern and western sectors that reaches a maximum depth of 65 cm, making it at its deepest some 120 cm lower than the floor elevation in ABC-69a (see elevation, pFig9). It remains unclear if this feature is natural, was created deliberately at the time of construction and thus served a purpose within the structure, or if it was dug out at a later time, i.e., as the result of past digging or previous archaeological excavations. The presence, however, of vertically oriented narrow white lines, or ‘pick-like’ marks, readily visible in some of the side-surfaces of the cavity perhaps favors the latter being the case. A darkbrown deposit of mud brick-like material covers the southern sector of the floor (pFig9). This side of the structure is exposed directly to the effects of prevailing wind and weathering, this factor, vis-à-vis the depositional pattern off to one side of the wall, likely argues for this feature being a mudflow from the original brickwork.
A single, carved, rectangular slab of white limestone remains in situ passing through the southeast side of the mud brick wall (pFig9). The slab measures some 95 cm long, 35 cm wide (outside) and 20 cm wide (inside), and 15 cm thick. There is a square-shaped basin carved into the upper surface of the larger, outer, portion of the block which in turn transitions into a roughly 8–10 cm wide carved channel running the length of the block. The pitch is towards the interior (pFig10). The design of the block also seems to match the one depicted in Abu-Bakr’s sketch (pFig5), shown passing through the wall of structure ABC-69a on a line towards the limestone basin in situ within. Although eroded, especially the portion exposed outside the wall, it seems clear that the block in situ in ABC-69b served to channe liquid into the interior.
As in ABC-69a, entrance and egress for ABC-69b was gained through two limestone block passageways (pFig86,9), situated here in mirror image to those in the former. The longer, southwest oriented, passageway measures about 250 cm long, 50 cm wide, and 50 cm high. This passageway, like its counterparts, has a flooring of hewn limestone blocks, although here many are lost and none of those that do survive still retain slots. Only one wall block remains along the northwest side of the passageway. The largest wall block surviving on the southeast side measures 105 cm long, 50 cm high, and 15 cm thick, similar to its counterparts in the southeast passageway of ABC-69a. It also retains a carved, 10 cm wide, slot like its counterparts elsewhere. As noted, one apparent roof block was found lying in the interior of the structure, just inside the passageway, which was moved temporarily to the northern portion of the interior for its protection (visible in pFig9). At the distal end of this passageway, an apparent blocking stone remains in situ (pFig9). The block is positioned upright and is reinforced by two large stones placed against its outer surface. A temenos wall, now composed of only limestone cobbles, encloses the
west and south sides of the Ipi-Persen mastaba complex (pFig3,4). This passageway, unlike the southeast passageway of ABC-69a, terminates within, instead of beyond, this southern temenos wall.
As in ABC-69a, a shorter limestone block passageway is built on the south side of the structure. Its construction is similar to its counterpart in ABC-69a, being some 50 cm interior width and 50–60 cm high, although it is longer, at 160 cm. The slabs forming the east wall are decayed badly, and now measure between 50–60 cm in length at their bases. Limestone floor slabs likewise remain in situ, but none retain
carved slots. The distal slab of the western wall of the passageway retains a single 5 cm wide carved slot; the slab opposite is heavily decayed and retains no such trace. The proximal block on the eastern wall of the passageway retains a single 8–10 cm vertical slot. The slot contains traces of pinkish colored tafl-plaster or mortar; whether or not this indicates something was once affixed here, or the surface
was smoothed to facilitate operating a sliding door, or if this is an artifact from an earlier use of the block elsewhere, remains under study. The slab opposite likewise is heavily eroded and retains no such trace. Again, whether or not this passageway, like its counterpart in structure ABC-69a, was ever longer than it is now most likely cannot be determined due to the present deflated state of the site.
IV. Discussion
Structures ABC-69a and ABC-69b are enigmatic. The archaeological data obtained about them to date, it must be reiterated, is preliminary in nature and subject to change. The information gathered to date does, however, open avenues of investigation and, hopefully, creates paths for further discussion.
Prof. Dr. Abu-Bakr offered the suggestion that these two structures were ‘cage
du hyène’. While this suggestion may yet be borne out, it must, at this point, remain for now just that, a possibility. Data gathered to date does not yet indicate what precisely these two structures were; however, it is sufficient to begin putting them into a context broader than just description. Perhaps by evaluating several possibilities of what they may have been, what they actually were can begin to come to light.
Given the location, in a cemetery, and their construction adjoining a mastaba, itself a part of a larger mastaba complex, that of Persen (LG-20, 21), an obvious suggestion could be made that these structures were tombs. If nothing else, data gathered to date appears to argue against this suggestion. If in fact they were domed once, combined with being freestanding circular structures, with two floored and roofed, hewn limestone block passageways each, such a configuration alone would make them uncommon, if not unique, among ancient Egypt’s mortuary structures (pFig1). As mentioned above (note 14) there are domed, beehive-shaped, and eggshaped tombs being uncovered elsewhere at Giza, in the Workmen’s Cemetery. In the lower sector of that cemetery, there are in fact a number of simple, two to six feet
high, domed mud brick tombs. These are quite different, however, from structures ABC-69a & b. In terms of mud brick construction technique, the two structures resemble superficially a circular serdab at Abydos reported by Frankfort. Like the Workmen’s tombs, however, the absence of above ground passageways or a serviceable interior basin makes the Abydos serdab quite different from the two Abu-Bakr Cemetery structures, certainly in form, and perhaps in function. The preponderance of uncommon, apparently non-mortuary, features, configured as found in ABC-69a & b, favors an argument against these structures ever having functioned as tombs.
Other well-attested examples of rounded or ovoid structures in ancient Egypt are granaries, or silos. Again, however, data available to date on structures ABC-69a & b argues against this suggestion. D.Arnold notes that granaries and silos occur primarily in settlement and temple contexts, which is clearly not the
case here. The construction techniques of granaries and silos, vis-à-vis structures ABC-69a & b, highlight their differences, not their similarities. An exhaustive discussion of granaries and silos per se is not included in this report.
Additional occurrences of circular or ovoid structures in ancient Egypt are ovens and pottery kilns. The very location of structures ABC-69a & b alone, in an isolated sector of the Western Field and directly against a limestone mastaba wall, likely argues that they functioned as neither ovens nor kilns. Food production areas, including bakery facilities with ovens, are attested elsewhere at Giza; however, these occur in a settlement context, the village of the pyramid workers.
Pottery manufacture, including kiln facilities, is attested in a funerary context, albeit not in the actual cemetery, at the pyramid temple of Khentkawes at Abusir, however, its presence in such a context is considered ‘surprising’. Pottery kilns are well attested elsewhere in ancient Egypt, for example, those excavated in building Q48.4 at Amarna. When comparing these with structures ABC-69a & b,
however, significant differences emerge.33 For example, the Amarna kilns were sunk into the ground, unlike ABC-69a, and although ABC-69b has a cavity sunk into the ground in one sector, it is unclear whether or not this feature is ancient or modern. The mudbrick bonding pattern in the Amarna kilns differs from that in ABC-69a & b, as do brick sizes.34 More importantly, the lengthy limestone block
passageways of both ABC-69a & b are not present on the Amarna kilns, which instead possess single stoke holes. That structures ABC-69a & b did not function as ovens or kilns is perhaps best evidenced by the fact that neither structure was found to contain evidence of burning or heat; for example, ash deposits were not encountered, mud bricks do not exhibit signs of burning, nor do the limestone walls of the adjacent mastabas; bones, many of them small and fragmentary, some recovered embedded in the ‘living floor’ layer inside ABC-69a, were not burnt, and the portion of the limestone block floor in ABC-69a exposed in the 2004 season did not appear burnt.
Circular constructions that once apparently were part of a centralized mortuary cult are attested at Abusir, at the mortuary complex of Mernefu, Khekeretnebty, and Neserkauhor. In the courtyard area central to the mastabas is an arrangement of four circular mudbrick offering tables, most likely focused on the cult of Khekeretnebty. While the diameters of these structures, from 98 cm to 112 cm, approach those of
structures ABC-69a & b, they are all quite low, ranging from only 6 cm to no more than 24 cm high. Their association with a limestone offering table and shallow basins further strengthens an argument that they served a cultic function and thus are quite different from ABC-69a & b.
At this time, therefore, available data seemingly favors an argument that structures ABC-69a & b were not constructed as tombs, granaries, silos, or kilns.
Whether or not these structures could, in some capacity, once have constrained an as yet unidentified type of animal(s), hyenas being among the possibilities, requires further discussion.
The location of ABC-69a & b, in an outlying sector of the Western Field beyond
which lays desert, against the southern wall of a pre-existing mastaba and bisecting
a temenos wall of a larger mastaba complex, is an enigma in its own right.
Note. A hyena depicted in the Old Kingdom mastaba of Iymery at Giza is shown tethered next to a young animal, possibly a cow, along with a gazelle. Texts accompanying the scene translate as ‘fattening’ and ‘bringing invocation offerings from the towns of the funerary estate at every festival celebration, every day, forever’,79 thereby identifying this hyena as a food product. The practice of consuming hyenas would make the Egyptians a rarity among ancient peoples in doing so, however, it is argued that the existence of the practice should not be considered strange.