The eastern cell of the upper chamber.
This cell has a "horseshoe" shaped plan, a short passage leads to the two portal
slabs that are almost buried in the masonry on their fronts.
The passage section is floored by the second eastern lintel and the passage by
the eastern lintel, differences in the thickness of these two slabs
result in the chamber floor being much lower than the main chamber and passage
floors. Grant discovered that the discrepancy had been made up
by using a layer of clay on the chamber floor.