Do you have a specific reference. "The book of the dead" covers a range of texts. I have a copy of the "papyrus of ani", which is perhaps the best know such document. If I get time I'll see if I can find anything in it.

Hm, yes I once studied the Book of the Duat but never made the connection between the waters and the mound.
Maybe I should dig my old books out of the attic
and brush up on my Hiroglifix.
PeteG
Ps. Has anyone seen the mound on the right side of Green st going east out of Avebury? (Opens a new can of worms and runs away...)