604 



PROF. J. W. GREGORY ON 



Nov. J 91 1, 



Cyrenaica may, therefore, be described as a plateau formed by a 

 westward extension of the Eocene limestones of Egypt, and capped 

 by outliers of the Maltese beds. 



The Miocene rocks, which, on the coast of Western Egypt, are but 

 little above sea-level, 1 occur in Eastern Cyrenaica at the height of 

 1100 to 1800 feet ; and, while the base of the Derna Limestone, 



Fig. 4. — Sketch-map illustrating the tectonic relations 

 of Cyrenaica. 



[For ' Marsa Susa ' read ' Mersa Susa.'] 



which is correlated with the Lower Mokattam Beds of Egypt, lies 

 close to the sea-level at Derna, it disappears beneath it farther 

 east. Westward, on the other hand, the Derna Limestone at Mersa 

 Susa extends from about 500 to 1100 feet above sea-level, it 



1 They are marked on Dr. Ball's map of Mersa Matruh up to the height of 

 about 200 feet. 



