Deep within the cave Petrie found a limestone stela of Pharaoh Ramesses I - a slab upon which Ramesses (who is traditionally reckoned by Egyptologists to have been an opposer of the Aten cult) surprisingly described himself as "The ruler of all that Aten embraces". Also found was an Amarna statue-head of Akhenaten's mother, Queen Tiye of Egypt, with her cartouche set in the crown.
Absolutly a sign that during the period of Akhenaten sombody brought this stuff there for safe keeping.
Mt. Horeb is Mt. Moses.