606 PROF. J. W. GREGORY ON [Nov. IQH, 



of the coast between that port and Has el Tin, trends about 20° to 

 the south of east. It thus approximates toward the direction 

 of the powerful faults which, as shown by M. Deprat, 1 formed the 

 islands of Euboea, Andros, and Tinos, and separated Euboea from 

 the mainland of Greece by the rift-valley of the Talanta and 

 Euripo Channels. 



The members of the second group of Cyrenaican faults trend 

 from south-west to north-east. They give rise to the scarps that 

 bound the plains of Merj and Silene, as Upper Eocene limestones at 

 Merj occur at a lower level than the Middle Eocene limestones 

 of the plateau to the south-east of the town. The Merj fault- 

 scarp is parallel to the Tokra fault-scarp, down which we descended 

 on to the coastal plain about 16 miles east of Benghazi. The hills 

 are formed of Lower Eocene rocks, and that the limestones at 

 their foot are Miocene is clear from the large Clypeasters and 

 Scutellas exposed on the wind-swept surfaces. The Tokra fault 

 must have a downthrow of at least 1500 feet. This fault-scarp 

 trends towards Ptolemeta, but its precise course is uncertain. 

 The position accepted for its northern continuation on the map 

 (fig. 4, p. 604) is based on the Admiralty Charts, Eastern Mediter- 

 ranean (2158 B, corrected to 1907) and Benghazi to Derna (1031, 

 corrected to 19U0) ; but, according to Camperio, 2 the fault-scarp 

 may pass nearer to Tokra, for his m;ip marks the high plateau 

 as reaching nearly to the shore and ending to the east of Tokra in 

 a steep descent which trends from about west-south-west to east- 

 north-east. The Admiralty Charts, however, represent the scarp 

 as passing farther inland on a fairly straight course, from its 

 position east of Benghazi to Ptolemeta. The International Geo- 

 logical Map of Europe (Sheet D VII, 1905) agrees more closely in 

 this respect with the Admiralty Chart than with Camperio's map. 



The Tokra scarp, as above accepted, is parallel to the Merj scarp 

 and is in line with the sharp division in Western Crete between the 

 Jurassic rocks and the metamorphic area south of Kanea. The 

 downthrow of the faults would no doubt be on opposite sides in 

 Crete and Cyrenaica ; but the coincidence of direction is remarkable, 

 especially as the continuation of this line into Asia Minor separates 

 the down thrown Kainozoic area of the Smyrna district from the 

 metamorphic rocks of the highlands to the south-east of Smyrna 

 and Ak Hissar. This line across Western Crete and from Smyrna 

 to Ak Hissar is almost at right angles to the direction of the Eu- 

 bcean faults. 



The third group of Cyrenaican faults trends approximately north 

 and south. It includes the GubahEault, the continuation of which 

 may form the headland of lias al Hilil. The evidence from this 

 fault supports Spratt ? s suggestion that the sharp bends of the coast 

 on the western sides of Bomba Bay, of the Bay of Salum, and perhaps 



1 J. Deprat, ' Etude G-eologique & Petrographique de l'lle d'Eubee ' 

 Besanc^on, 1904. 



2 ' Carta Economica della Tripolitana & Cirenaica,' published by the 

 Societa di Esplorazioue cornmerciale in Africa, Milan, 1883. 



