In 1837 Howard Vyse looked for a Southern entrance to the Great
Pyramid. After removing about 30 feet of blocks, he gave up.

[1.bp.blogspot.com]

In his published results he says this:

> The stones were very large, and the half of each of them
> was keyed in under the upper layer, besides which, many
> of them were in slanting directions, although in horizontal
> courses

I'm not sure what he means by half of each stone being keyed under the
layer above it. From the images I found, it doesn't appear that any
stones are keyed. It also doesn't look like the stones are slanted. Does
anyone have any more information or better pictures showing what he was
referring to? Here's a link to his publication:

[archive.org]