There were parts of the narrow valley of the Nile where the cliffs of the desert so advanced upon the river as to leave absolutely no room for the erection of temples occupying so much ground. The inhabitants here had recourse to grotto temples; that is to say, they transferred the principal rooms of the sanctuary to an excavation in the cliff. When the space between rock and stream permitted it, the courts and pylons were built, and only the hypostyle hall and the holy of holies, reduced to the minimum necessary for the performance of the rites, were cut from the rock. This is the case in El-Cab, Redesie, Silsilis, and Girsheh. The last of these, the largest, had a court with Osiris piers upon the sides and with four columns upon the front, which seems never to have been flanked by pylons. Its largest excavated space, apparently corresponding to a second court, is also decorated upon the longer sides with Osiris piers. Thereupon follows a narrow hall, which but inadequately represents the hypostyle; and, finally, as the holy of holies, a small chamber with an altar.
Far more important than these are the grotto temples of Abou-Simbel, in the vicinity of the second cataract, where the portals are also cut wholly from the rock. The larger of the two even attempts to approach, as well as is possible, the enormous pylons of the great Theban temples. (Fig. 24.) To this end the gentle inclination of the cliff was cut away to the talus angle of the Egyptian walls and pylons, and the cornice above, of roundlet and scotia, was worked from the rock. Four such colossal sitting figures, as are often placed before the pylons, were also cut from the cliff—an effective ornament and an economy of labor thus being secured. The representation of the portal between two pylons was given up; the whole front formed one wall in which the entrance-door was cut without further decoration. The empty space above the opening was filled by a high-relief, carved within an oblong niche. (Fig. 24.) The entrance, which has now been cleared of the sand, leads in natural order to a space corresponding to the court of the free-standing temples; it is somewhat similar to that of Girsheh, which was also erected by Ramses II., though more imposing and of better proportions. (Fig. 25.) A following room, the ceiling of which is supported by four piers, suggests the temple hypostyle, here much dwindled in extent from the difficulty of its excavation as well as from the general restriction of this space in Nubian monuments compared with those of Central Egypt. The innermost chambers of the holy of holies are not only as small as those of the free-standing temples, but are reduced in number.
The second rock-cut temple of Abou-Simbel, situated near the one described, is of smaller dimensions. It has upright colossal statues upon the front, which, instead of being cut in the round, have more the effect of reliefs from the fact that they stand in niches, a difference arising from the greater steepness of the cliff at this point. The treatment appears rational in consideration of the smaller amount of material thereby removed, though the unmonumental effect of the reliefs, which lean with the inclination of the wall, is an unfortunate result of this economy. The first hall, analogous to the temple court, has its ceiling supported by six piers, which are decorated upon the side towards the central aisle by Athor masks. Three entrances lead from this hall into a narrow space, here entirely at variance with the character of a hypostyle, and through this into the holy of holies. Notwithstanding the contraction of the two inner departments, the three principal divisions of the free-standing buildings can be recognized in all rock-cut temples.
The existing ruins allow a comparatively clear understanding of the religious architecture of Egypt, in which class the monumental tombs must be reckoned as well as the various forms of temples; but we are left almost entirely uninstructed as to the nature of the private dwellings. The plan of the cloisters within the great temple of Carnac (compare Fig. 20.) is indeed clear, though, being only a portion of a larger scheme, it had no individual or exterior expression. The manner in which these spaces were roofed and lighted is not evident.