In other pyramids we find different combinations again. In the double-sloped erection at Dashour, the courses of casing stones are vertical instead of horizontal,[224] while a brick pyramid--the most northern--in the same locality, was covered with slabs of limestone, fixed, no doubt, with mortar. [224] _Description de l'Égypte, Antiquités_, vol. v. p. 7. Sometimes we find the revetment in a state of semi-completion; the blocks in place, and cut to the proper angle, but without their final polish. Such is the case with the Second Pyramid, upon which blocks of granite are to be found which are still rough in face. It would seem that the patience required for the minute completion of such a terribly long and tedious piece of work was not forthcoming. But we ought in fact to be surprised, not so much at the unfinished state of a pyramid here and there, but rather that they should ever have been completed. The variety which is so conspicuous in the architectural construction of the pyramids is also to be found in their epigraphy. The first explorers of the Pyramids of Gizeh were surprised at the absence of all inscriptions beyond the masons' marks; the silence of those enormous structures seemed amazing; but soon Colonel Vyse discovered in the pyramid of Mycerinus the sarcophagus of that king, and the mummy case, now in the British Museum, which bears an inscription of some length. Recent discoveries, too, of which full details are yet wanting, prove that some of the pyramids contained long texts, which contain the names of kings and other information which is of great importance to the historian of the Egyptian religion. In 1879 and 1880, Mariette caused three pyramids at Sakkarah to be opened, which until then had remained unexplored. One of them was silent and empty, but in the others the inscriptions and sarcophagi of two kings of the sixth dynasty, Papi and his son Merenzi, were found. Fragments of a Ritual of the Dead were recognized among them. Pleasure at this discovery, the last which he was destined to make in the soil of Egypt, brightened the last days of Mariette.[225] [225] G. CHARMES, in the _Journal des Débats_, February 8, 1881.