Vol. 67.] THE GEOLOGY OF CYRENAICA. 573 



Cyrenaica is, however, geologically the least-known area on the 

 shores of the Mediterranean. The geology of the parts of Egypt 

 near the eastern frontier of Cyrenaica is known from the work of 

 Zittel 1 and Fuchs 2 at Siwa, and from collections made on the coast 

 of Marmarica at Mersa Tobruk by Schweinfurth, 3 and on the Libyan 

 coast by Ball 4 and by Pachnndaki 5 at Mersa Matruh, about half-way 

 between Alexandria and the Bay of Salum. The correlation of 

 the rocks on the eastern frontiers of Cyrenaica has been care- 

 fully discussed by Dr. Blanckenhorn. 6 An admirable summary of 

 the geological data regarding Cyrenaica was published in 1904 by 

 Dr. Hildebrand, who shows that the existing information was then 

 both scanty and uncertain. 7 



From the evidence available in 1908, three different explanations 

 of the geological structure of Cyrenaica were possible. It might be 

 a fragment of a mountain-loop that had once connected the Atlas 

 with the mountain-ranges of Crete and Asia Minor ; or it might be 

 a plateau of Eocene rocks — an outlier of the Mokattam Series of 

 Egypt ; or again, it might be a horst of Miocene and Pliocene lime- 

 stones, once continuous with those of Malta. 



The first theory — the connexion between Cyrenaica and the 

 Atlas — was suggested by several considerations, including the 

 probability that the mountains of Cyrenaica had an axial core of 

 ancient rocks. 



The first information as to the geological structure of Cyrenaica 

 was collected by Delia Cella, an Italian doctor who accompanied a 

 military expedition led by the Bey of Tripoli into Cyrenaica in 1817. 

 Delia Cella clearly recognized that the mountains of Cyrenaica were 

 not a simple continuation of the Atlas, though he regarded both 

 areas as composed of similar rocks. He remarks : — ■ 



' In some of my letters, I have attempted to shew, that the mountains of 

 the Cyrenaica form no part of the eastern prolongation of that chain which 



1 K. A. von Zittel, ' Beitrage zur Geologie & Palaontologie der Libyschen 

 Wiiste & der angrenzenden Gebiete von yEgypten ' Paheontographica, vol. xxx, 

 pt. 1 (1883) pp. cxxiv-cxxxvi. 



2 Th. Fuchs, ' Beitrage zur Kenntniss der Miocan-Fauna iEgyptens & der 

 Libyschen Wiiste ' Ibid. pp. 18-60 & pis. vi-xxii. 



a G. Schweinfurth, ' Ein Besuch in Tobruk an der Kuste von Marmarica 

 Marineverordnungsblatt, No. 47 (1883) pp. 14-29. For reference to the 

 discovery of these fossils, see Gr. Hildebrand, ' Cyrenaika als Gebiet kiinftiger 

 Besiedelung' Bonn, 1904, pp. 78-79, and M. Blanckenhorn, 'Neue? zur Geo- 

 logie & Palaontologie vEgvptens, III. Das Miocan ' Zeitschr. Deutsch. Geol. 

 Gesellsch. vol. liii (1901) pp. 104-105. 



4 Maps of the Districts of Mersa Matru & Ras Allem Enm ' showing . . . and 

 the Main Outlines of the Surface-Geology' — scale 1 : 25,000. Cairo, 1903. 



5 D. E. Pachundaki, ' Sur la Constitution Geologique des Environs de Mirsa 

 Matrouh (Marmarique) 'JO. R. Acad. Sci. Paris, vol. cxxxvii (1903) pp. 350-51 ; 

 also ' Contribution a l'Etude Geologique des Environs de Marsa Matrouh 

 (Marmarique) ' Revue Internationale cl'Egypte, vol. iv (1907) 36 pp., pt. ii. 



6 M. Blanckenhorn, ' Neues zur Geologie & Palaontologie iEgyptens, II. 

 Das Palseogen ' Zeitschr. Deutsch. Geol. Gesellsch. vol. lii (1900) table facing 

 p. 406 ; and ' III. Das Miocan' ibid. vol. liii (1901) table facing p. 52. 



7 G. Hildebrand, ' Cyrenaika als Gebiet kiinftiger Besiedelung ' Bonn, 1904, 

 pp. 77-95. 



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