As the trail was very difficult and the mule's pace was slow, I found myself dozing at times, and at last I must have fallen asleep.

I think I must have been awakened by a singular regularity in the movement of the mule--or else it was the monotony of step that had put me to sleep and the cessation of it awakened me.

You see, at first I was not certain that I wasn't really dreaming.

For the trail seemed to have disappeared; the wall of rock on one side had vanished also, and there appeared to be nothing ahead of me but the opposite hillside." Uncle Sylvester stopped to look out of the window at a passing carriage.
Then he went on.

"The moon came out, and I saw what had happened.