Side elevation of the granite sarcophagus discovered in the pyramid of Menkaure at Giza.

This illustration shows the similarity between the façade of the Menkaure sarcophagus and  the structure portrayed beneath the Great Sphinx on the Dream Stele of Thutmose IV. 

Vyse documented that "It was entirely empty, and composed of basalt, which bore a fine polish of a shaded brown colour, but was blue where it had been chipped off, or broken. Some sharp substance, such as emery powder, had been used in its construction, and it appeared to have been sawn, which is remarkable, as the art of sawing marble was not known at Rome till a late period."

Sadly he also records "As the sarcophagus would have been destroyed, had it remained in the pyramid, I resolved to send it to the British Museum...It was embarked at Alexandria in the autumn of 1838, on board a merchant-ship, which was supposed to have been lost off Carthagena, as she never was heard of after her departure from Leghorn on the 12th of October in that year, and as some parts of the wreck were picked up near the former port"

Source: Howard Vyse,  Operations Carried On at the Pyramids of Gizeh (1840)