has four entrances and a series of internal passages, horizontal galleries, staircases and cells, which make it little else than a subterranean labyrinth. It is singular also in having, upon its central axis and at the point upon which, at various heights, all its galleries converge, a sort of large well, a chamber about twenty feet square and eighty feet high, in the pavement of which a huge block of granite cut into the shape of a cork or plug was so placed as to open at will[1] and leave a free passage for the descent into a second chamber, the purpose of which is more than obscure, as it is too small even to have contained a sarcophagus.[2] The end of the long passage which leads to the thirty chambers which have been counted beneath this pyramid has been found in the neighbouring sands (Fig. 134).
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Fig.131.—The pyramid of Illahoun, horizontal section in perspective; from the plan of Perring.
Another point of difference: most of the pyramids are built round a core of living rock, which is embraced by the lower courses of their masonry. But the pyramid of Mycerinus is just the reverse of this. It is built over a hollow in the rock which is filled up with masonry. The inequalities of the surface were usually taken advantage of so as to economize material, and make
