Actually, Edgar Cayce never claimed that the Hall of Records was located under the Sphinx. What he did say is, there is information about who built
the Sphinx and the ruler of that time period in a chamber beneath it. But that is a far cry from the actual Hall of Records, which he said was located
in a pyramid of its own, yet to be discovered, and that it will only be discovered at the correct time in the correct way by the right people.
Cayce did also mention that there is a tunnel that leads from beneath the Sphinx to this Hall of Records. But again he said it won't be found and
can't be entered until mankind is ready to discover it.
Threads like this often make me think of this famous Shakespeare quote:
"There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy."
[edit on 25-9-2007 by tinfoil hatter]