GREAT PLATEAU OF FEZZAN. 
141 
by artificial means. We came to a solitary rock on 
the plain, containing excavations that seemed to be 
the work of men. Here, we were told, Dr. Oiidney 
once stopped and breakfasted. 
We have now a pretty correct idea of the great 
central table-land of Fezzan. It is an elevation, not 
quite clearly marked to the eye on some of its 
northern approaches, but dropping sheer to the 
plain at other parts. Mourzuk is situated in a 
sandy depression on its surface, which would 
probably be turned into a salt lake if there were 
sufficient rain. The limits of the hollow, as of 
that of many others — Wady Atbah for example — 
are not noticed by the traveller. Whether he 
approaches or leaves Mourzuk, he seems still to be 
traversing a level plain, and only finds his mistake 
by noticing the change in the nature of the ground, 
the presence of marshes, of green vegetation, and of 
a heavy, stifling atmosphere. 
