Westward of _Siwah_, I found two banks or heaps of calcined shells, some of the size of two inches over. My interpreter told me, that taking his road at some distance from me, he saw a mountain standing singly and unconnected with others, composed entirely of shells. Many such vast isolated mounds are to be seen throughout the whole of this district, and the bed-joints or interstices of their strata of stone (always horizontal), being filled up with a reddish, friable, calcareous substance, they often resemble pyramids, and in so exact and illusive a manner, that more than once I was deceived into expectation of arrival at such building. The architecture of the ancient Egyptians was of the vast and gigantic kind; and builders of such ambitious temper and stupendous scheme, might readily entertain the idea of transforming a mountain into a pyramid, shaping the huge rock, already in form partly adapted, and casing it with wrought stones on the outside, as they might prefer. Some of the learned have given an opinion, that the Pyramids of _Giza_ and of _Saccara_, were not originally erections from the base, but merely hills of earth or stone, shaped and covered by the labour of man. The idea is plausible, though certainly to be controverted, by reasons to be drawn from history, and from other the best sources of fact and argument. I now proceed to the recital of an event in which I was personally and principally concerned. I shall give the recital in detail, as, in its consequences, being of the highest import to the future safety of myself, and therewith to the progress of discovery which I have engaged in; and, as it has afforded me self-confidence and new encouragement, ever favourable to the success of enterprize, so will it, I trust, give satisfaction to those who have employed me, inspiring just and well-founded hopes of my finally accomplishing the great purpose entrusted to my care.