Looking down, he saw the remains of a wall of solid masonry, and perceived that he had been correct in his surmise as to the purpose of the ledge.

Then they turned, and went back to the other end of the ledge.

A few feet before they reached this, Meinik--who was now leading the way--stopped.
"Here is a passage, master." The entrance was about the same size as that through which they had stepped out on to the ledge but, instead of going straight in, it started upwards.
"Another flight of steps, Meinik.

I am beginning to hope that we shall find some way out, at the top.

If we can do so, it will make us safe.