One small window, with two panes of glass was set high under the eaves on the side toward Casey.

Cleverly concealed it was, built to resemble the ledge.

Visible from one side only, and that was the side where Casey stood.

At the back the sloping boulder, untouched, impregnable; at the north and west, a twist of the ledge that hid the cabin completely in a niche.

It was the window on the south side that betrayed it.
So here was what the boulder concealed,--and yet, Casey was not satisfied with the discovery.